Publications by authors named "Kim Pettersson"

153 Publications

A prognostic model for colorectal cancer based on CEA and a 48-multiplex serum biomarker panel.

Sci Rep 2021 Feb 22;11(1):4287. Epub 2021 Feb 22.

Research Programs Unit, Translational Cancer Medicine, University of Helsinki, Meilahti Hospital, Haartmaninkatu 4, PO Box 340, 00029 HUS, Helsinki, Finland.

Mortality in colorectal cancer (CRC) remains high, resulting in 860,000 deaths annually. Carcinoembryonic antigen is widely used in clinics for CRC patient follow-up, despite carrying a limited prognostic value. Thus, an obvious need exists for multivariate prognostic models. We analyzed 48 biomarkers using a multiplex immunoassay panel in preoperative serum samples from 328 CRC patients who underwent surgery at Helsinki University Hospital between 1998 and 2003. We performed a multivariate prognostic forward-stepping background model based on basic clinicopathological data, and a multivariate machine-learned prognostic model based on clinicopathological data and biomarker variables, calculating the disease-free survival using the value of importance score. From the 48 analyzed biomarkers, only IL-8 emerged as a significant prognostic factor for CRC patients in univariate analysis (HR 4.88; 95% CI 2.00-11.92; p = 0.024) after correcting for multiple comparisons. We also developed a multivariate model based on all 48 biomarkers using a random survival forest analysis. Variable selection based on a minimal depth and the value of importance yielded two tentative candidate CRC prognostic markers: IL-2Ra and IL-8. A multivariate prognostic model using machine-learning technologies improves the prognostic assessment of survival among surgically treated CRC patients.
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http://dx.doi.org/10.1038/s41598-020-80785-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900104PMC
February 2021

Double-Antigen Lateral Flow Immunoassay for the Detection of Anti-HIV-1 and -2 Antibodies Using Upconverting Nanoparticle Reporters.

Sensors (Basel) 2021 Jan 6;21(2). Epub 2021 Jan 6.

Department of Biotechnology, University of Turku, 20520 Turku, Finland.

Rapid diagnostic tests (RDTs) are often used for the detection of anti-human immunodeficiency virus (HIV) antibodies in remote locations in low- and middle-income countries (LMIC) with low or limited access to central laboratories. The typical format of an RDT is a lateral flow assay (LFA) with visual interpretation prone to subjectivity. This risk of misinterpretation can be overcome with luminescent upconverting nanoparticle reporters (UCNPs) measured with a miniaturized easy-to-use reader instrument. An LFA with UCNPs for anti-HIV-1/2 antibodies was developed and the assay performance was evaluated extensively with challenging patient sample panels. Sensitivity ( = 145) of the UCNP-LFA was 96.6% (95% CI: 92.1-98.8%) and specificity ( = 309) was 98.7% (95% CI: 96.7-99.7%). Another set of samples ( = 200) was used for a comparison between the UCNP-LFA and a conventional visual RDT. In this comparison, the sensitivities for HIV-1 were 96.4% (95% CI: 89.8-99.3%) and 97.6% (95% CI: 91.6-99.7%), for the UCNP-LFA and conventional RDT, respectively. The specificity was 100% (95% CI: 96.4-100%) for both assays. The developed UCNP-LFA demonstrates the applicability of UCNPs for the detection of anti-HIV antibodies. The signal measurement is done by a reader instrument, which may facilitate automated result interpretation, archiving and transfer of data from de-centralized locations.
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http://dx.doi.org/10.3390/s21020330DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7825344PMC
January 2021

Three two-site apoA-I immunoassays using phage expressed detector antibodies - Preliminary clinical evaluation with cardiac patients.

J Pharm Biomed Anal 2021 Feb 20;194:113772. Epub 2020 Nov 20.

Department of Biochemistry, Division of Biotechnology, University of Turku, Turku, Finland.

High density lipoproteins (HDL) are a heterogenous group of subpopulations differing in protein/lipid composition and in their anti-atherogenic function. There is a lack of specific and robust assays which can target the functionality of HDL with respect to atherosclerosis. With recently generated CAD HDL targeted, single chain recombinant antibodies (scFvs) we set out to design and optimize apo A-I tests to compare it with conventional HDL-C and apo A-I analyses for diagnosis and risk assessment of coronary artery disease (CAD) and its outcome. Three highly sensitive two-site apo A-I assays: 022-454, 109-121 and 110-525 were optimized. A preliminary clinical evaluation of these assays, after proper sample dilution procedure, was performed using samples derived from 195 chest pain patients (myocardial infarction (MI), n = 86 and non-MI, n = 109), collected at the time of admission and at discharge from hospital (hospital stay ≤ 24 h). The clinical performance of the assays was compared with apo A-I measured with polyclonal anti-apo A-I antibody using conventional ELISA. Apo A-I data was in addition compared with HDL-C concentration of the samples. The concentration of apo A-I was significantly lower in MI patients than in non-MI individuals with assay 022-454 (admission and discharge samples, P < 0.0001 and = 0.004); assay 109-121 (admission and discharge samples, P = 0.04 and 0.0009), and, ELISA based apo A-I test (admission and discharge samples, P = 0.008 and < 0.0001). HDL-C (admission and discharge samples, P = 0.002 and P = 0.01) was also significantly lower in MI patients. In Kaplan- Meier analysis, two-site assay 109-121 assay predicted mortality from admission samples at 1.5 yrs (whole cohort, P = 0.01 and in MI patients, P = 0.05) and at 6 months (whole cohort, P = 0.04). Assay 110-525 predicted mortality at 1.5 yrs from admission samples of non-MI patients (P = 0.01) and at 6 months from whole discharge sample cohort (P = 0.04). Polyclonal anti-apo A-I based conventional assay predicted mortality at 1.5 yrs from admission samples of whole cohort (P = 0.03). Two-site apo A-I assay 022-454 and HDL-C provided no capability of predicting mortality in the whole cohort or any sub-group. In conclusion, two of the tested recombinant apo A-I antibody combinations (sc 109-121 and sc 110-525) display promising outcome to improve diagnosis and prediction of future cardiac events in cardiac patients over polyclonal apo A-I ELISA and HDL-C assays. The noted differences, while interesting, are preliminary and need however to be verified in extensive cohorts of pathological cardiac conditions and healthy controls.
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http://dx.doi.org/10.1016/j.jpba.2020.113772DOI Listing
February 2021

Prospective validation of microseminoprotein-β added to the 4Kscore in predicting high-grade prostate cancer in an international multicentre cohort.

BJU Int 2020 Dec 11. Epub 2020 Dec 11.

Departments of Laboratory Medicine, Surgery, and Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.

Objectives: To prospectively evaluate the performance of a pre-specified statistical model based on four kallikrein markers in blood (total prostate-specific antigen [PSA], free PSA, intact PSA, and human kallikrein-related peptidase 2), commercially available as the 4Kscore, in predicting Gleason Grade Group (GG) ≥2 prostate cancer at biopsy in an international multicentre study at three academic medical centres, and whether microseminoprotein-β (MSP) adds predictive value.

Patients And Methods: A total of 984 men were prospectively enrolled at three academic centres. The primary outcome was GG ≥2 on prostate biopsy. Three pre-specified statistical models were used: a base model including PSA, age, digital rectal examination and prior negative biopsy; a model that added free PSA to the base model; and the 4Kscore.

Results: A total of 947 men were included in the final analysis and 273 (29%) had GG ≥2 on prostate biopsy. The base model area under the receiver operating characteristic curve of 0.775 increased to 0.802 with the addition of free PSA, and to 0.824 for the 4Kscore. Adding MSP to the 4Kscore model yielded an increase (0.014-0.019) in discrimination. In decision-curve analysis of clinical utility, the 4Kscore showed a benefit starting at a 7.5% threshold.

Conclusion: A prospective multicentre evaluation of a pre-specified model based on four kallikrein markers (4Kscore) with the addition of MSP improves the predictive discrimination for GG ≥2 prostate cancer on biopsy and could be used to inform biopsy decision-making.
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http://dx.doi.org/10.1111/bju.15320DOI Listing
December 2020

Upconverting nanoparticle reporter-based highly sensitive rapid lateral flow immunoassay for hepatitis B virus surface antigen.

Anal Bioanal Chem 2021 Feb 23;413(4):967-978. Epub 2020 Nov 23.

Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, 121001, India.

Detection of hepatitis B Virus surface antigen (HBsAg) is an established method for diagnosing both acute and chronic hepatitis B virus (HBV) infection. In addition to enzyme immunoassays (EIAs), rapid diagnostic tests (RDTs) are available for the detection of HBsAg in resource-poor settings. However, the available RDTs have inadequate sensitivity and therefore are not suitable for diagnosis of patients with low levels of HBsAg and for blood screening. To provide a high-sensitivity RDT, we developed a lateral flow immunoassay (LFIA) for HBsAg utilizing upconverting nanoparticle (UCNP) reporter. The UCNP-LFIA can use whole blood, serum, or plasma and the results can be read in 30 min using a reader device. When compared with a commercial conventional visually read LFIA, the developed UCNP-LFIA had a Limit of Detection (LoD) of 0.1 IU HBsAg/ml in spiked serum, whereas the LoD of the conventional LFIA was 3.2 IU HBsAg/ml. The developed UCNP-LFIA fulfills the WHO criterion for blood screening (LoD ≤ 0.13 IU HBsAg/ml) in terms of LoD. The UCNP-LFIA and conventional LFIA were evaluated with well-characterized sample panels. The UCNP-LFIA detected 20/24 HBsAg-positive samples within the HBsAg Performance Panel and 8/10 samples within the Mixed Titer Performance Panel, whereas the conventional LFIA detected 8/24 and 4/10 samples in these panels, respectively. The performance of the assays was further evaluated with HBsAg-positive (n = 108) and HBsAg-negative (n = 315) patient samples. In comparison with a central laboratory test, UCNP-LFIA showed 95.4% (95% CI: 89.5-98.5%) sensitivity whereas sensitivity of the conventional LFIA was 87.7% (95%CI: 79.9-93.3%).
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http://dx.doi.org/10.1007/s00216-020-03055-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7813740PMC
February 2021

Ultrasensitive and Robust Point-of-Care Immunoassay for the Detection of Malaria.

Anal Chem 2020 12 23;92(24):15766-15772. Epub 2020 Nov 23.

Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, Haryana, India.

malaria is widespread in the tropical and subtropical regions of the world. There is ongoing effort to eliminate malaria from endemic regions, and sensitive point-of-care (POC) diagnostic tests are required to support this effort. However, current POC tests are not sufficiently sensitive to detect in asymptomatic individuals. After extensive optimization, we have developed a highly sensitive and robust POC test for the detection of infection. The test is based on upconverting nanophosphor-based lateral flow (UCNP-LF) immunoassay. The developed UCNP-LF test was validated using whole blood reference panels containing samples at different parasite densities covering eight strains of from different geographical areas. The limit of detection was compared to a WHO-prequalified rapid diagnostic test (RDT). The UCNP-LF achieved a detection limit of 0.2-2 parasites/μL, depending on the strain, which is 50- to 250-fold improvement in analytical sensitivity over the conventional RDTs. The developed UCNP-LF is highly stable even at 40 °C for at least 5 months. The extensively optimized UCNP-LF assay is as simple as the conventional malaria RDTs and requires 5 μL of whole blood as sample. Results can be read after 20 min from sample addition, with a simple photoluminescence reader. In the absence of a reader device at the testing site, the strips after running the test can be transported and read at a central location with access to a reader. We have found that the test and control line signals are stable for at least 10 months after running the test. The UCNP-LF has potential for diagnostic testing of both symptomatic and asymptomatic individuals.
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http://dx.doi.org/10.1021/acs.analchem.0c02748DOI Listing
December 2020

HE4 in the evaluation of tumor load and prognostic stratification of high grade serous ovarian carcinoma.

Acta Oncol 2020 Dec 8;59(12):1461-1468. Epub 2020 Oct 8.

Department of Obstetrics and Gynecology, Turku University Hospital and University of Turku, Turku, Finland.

Objective: Human epididymis protein 4 (HE4) is a validated, complementary biomarker to cancer antigen 125 (CA125) for high grade serous ovarian carcinoma (HGSC). Currently, there are insufficient data on the utility of longitudinal HE4 measurement during HGSC treatment and follow up. We set to provide a comprehensive analysis on the kinetics and prognostic performance of HE4 with serial measurements during HGSC treatment and follow up.

Methods: This prospective study included 143 patients with advanced HGSC (ClinicalTrials.gov identifier: NCT01276574). Serum CA125 and HE4 were measured at baseline, before each cycle of chemotherapy and during follow up until first progression. Baseline biomarker values were compared to the tumor load assessed during surgery and to residual disease. Biomarker nadir values and concentrations at progression were correlated to survival.

Results: The baseline HE4 concentration distinguished patients with a high tumor load from patients with a low tumor load assessed during surgery (<.0001). The baseline CA125 level was not associated with tumor load to a similar extent (=.067). At progression, the HE4 level was an independent predictor of worse survival in the multivariate analysis (=.002). All patients that were alive 3 years post-progression had a serum HE4 concentration below 199.20 pmol/l at the 1st recurrence.

Conclusion: HE4 is a feasible biomarker in the treatment monitoring and prognostic stratification of patients with HGSC. Specifically, the serum level of HE4 at first relapse was associated with the survival of patients and it may be a useful complementary tool in the selection of second line treatments. This is to the best of our knowledge the first time this finding has been reported.
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http://dx.doi.org/10.1080/0284186X.2020.1827157DOI Listing
December 2020

Glycovariant-based lateral flow immunoassay to detect ovarian cancer-associated serum CA125.

Commun Biol 2020 Aug 21;3(1):460. Epub 2020 Aug 21.

Department of Biochemistry/Biotechnology, University of Turku, Turku, Finland.

Cancer antigen 125 (CA125) is a widely used biomarker in monitoring of epithelial ovarian cancer (EOC). Due to insufficient cancer specificity of CA125, its diagnostic use is severely compromised. Abnormal glycosylation of CA125 is a unique feature of ovarian cancer cells and could improve differential diagnosis of the disease. Here we describe the development of a quantitative lateral flow immunoassay (LFIA) of aberrantly glycosylated CA125 which is widely superior to the conventional CA125 immunoassay (CA125IA). With a 30 min read-out time, the LFIA showed 72% sensitivity, at 98% specificity using diagnostically challenging samples with marginally elevated CA125 (35-200 U/mL), in comparison to 16% sensitivity with the CA125IA. We envision the clinical use of the developed LFIA to be based on the substantially enhanced disease specificity against the many benign conditions confounding the diagnostic evaluation and against other cancers.
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http://dx.doi.org/10.1038/s42003-020-01191-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7442799PMC
August 2020

Evaluation of a New Skeletal Troponin I Assay in Patients with Idiopathic Inflammatory Myopathies.

J Appl Lab Med 2020 03;5(2):320-331

Department of Biochemistry/Biotechnology, University of Turku, Turku, Finland.

Background: The current biomarkers for diagnosis and monitoring of injured and diseased skeletal muscles, such as creatine kinase (CK), have limited tissue specificity and incapability to differentiate between pathological and physiological changes. Thus, new biomarkers with improved diagnostic accuracy are needed. Our aim was to develop and validate a novel assay for skeletal troponin I (skTnI), and to assess its clinical performance in patients with idiopathic inflammatory myopathies (IIM).

Methods: A two-step fluoroimmunoassay was used to analyze samples from healthy reference individuals (n = 140), patients with trauma (n = 151), and patients with IIM (n = 61).

Results: The limit of detection was 1.2 ng/mL, and the upper reference limit (90th percentile) was 5.2 ng/mL. The median skTnI concentrations were
Conclusions: With the skTnI assay, patients with IIM were identified from healthy individuals and from patients with traumatic muscular injuries. When compared to CK, skTnI appeared to be more accurate in managing patients with low-grade IIM disease activities. The developed assay serves as a reliable analytical tool for the assessment of diagnostic accuracy of skTnI in the diagnosis and monitoring of myopathies.
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http://dx.doi.org/10.1093/jalm/jfz016DOI Listing
March 2020

Exploratory Analysis of CA125-MGL and -STn Glycoforms in the Differential Diagnostics of Pelvic Masses.

J Appl Lab Med 2020 03;5(2):263-272

Institute of Biomedicine, Research Center for Cancer, Infections and Immunity, Department of Pathology, University of Turku and Turku University Hospital, Turku, Finland.

Background: The cancer antigen 125 (CA125) immunoassay (IA) does not distinguish epithelial ovarian cancer (EOC) from benign disease with the sensitivity needed in clinical practice. In recent studies, glycoforms of CA125 have shown potential as biomarkers in EOC. Here, we assessed the diagnostic abilities of two recently developed CA125 glycoform assays for patients with a pelvic mass. Detailed analysis was further conducted for postmenopausal patients with marginally elevated conventionally measured CA125 levels, as this subgroup presents a diagnostic challenge in the clinical setting.

Methods: Our study population contained 549 patients diagnosed with EOC, benign ovarian tumors, and endometriosis. Of these, 288 patients were postmenopausal, and 98 of them presented with marginally elevated serum levels of conventionally measured CA125 at diagnosis. Preoperative serum levels of conventionally measured CA125 and its glycoforms (CA125-MGL and CA125-STn) were determined.

Results: The CA125-STn assay identified EOC significantly better than the conventional CA125-IA in postmenopausal patients (85% vs. 74% sensitivity at a fixed specificity of 90%, P = 0.0009). Further, both glycoform assays had superior AUCs compared to the conventional CA125-IA in postmenopausal patients with marginally elevated CA125. Importantly, the glycoform assays reduced the false positive rate of the conventional CA125-IA.

Conclusions: The results indicate that the CA125 glycoform assays markedly improve the performance of the conventional CA125-IA in the differential diagnosis of pelvic masses. This result is especially valuable when CA125 is marginally elevated.
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http://dx.doi.org/10.1093/jalm/jfz012DOI Listing
March 2020

Prostate cancer risk SNP rs10993994 is a trans-eQTL for SNHG11 mediated through MSMB.

Hum Mol Genet 2020 Jun;29(10):1581-1591

Department of Genetics and Genomic Sciences, Icahn Institute for Data Science and Genome Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.

How genome-wide association studies-identified single-nucleotide polymorphisms (SNPs) affect remote genes remains unknown. Expression quantitative trait locus (eQTL) association meta-analysis on 496 prostate tumor and 602 normal prostate samples with 117 SNPs revealed novel cis-eQTLs and trans-eQTLs. Mediation testing and colocalization analysis demonstrate that MSMB is a cis-acting mediator for SNHG11 (P < 0.01). Removing rs10993994 in LNCaP cell lines by CRISPR/Cas9 editing shows that the C-allele corresponds with an over 100-fold increase in MSMB expression and 5-fold increase in SNHG11 compared with the T-allele. Colocalization analysis confirmed that the same set of SNPs associated with MSMB expression is associated with SNHG11 expression (posterior probability of shared variants is 66.6% in tumor and 91.4% in benign). These analyses further demonstrate variants driving MSMB expression differ in tumor and normal, suggesting regulatory network rewiring during tumorigenesis.
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http://dx.doi.org/10.1093/hmg/ddaa026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7526792PMC
June 2020

A longitudinal analysis of CA125 glycoforms in the monitoring and follow up of high grade serous ovarian cancer.

Gynecol Oncol 2020 03 27;156(3):689-694. Epub 2019 Dec 27.

Department of Obstetrics and Gynecology, Turku University Hospital and University of Turku, Turku, Finland. Electronic address:

Objective: Cancer antigen 125 (CA125) is generally considered the gold standard of biomarkers in the diagnosis and monitoring of high grade serous ovarian carcinoma (HGSC). We recently reported, that two CA125 glycoforms (CA125-STn and CA125-MGL) have a high specificity to HGSC and further hypothesized, that these cancer specific glycoforms are feasible candidates as biomarkers in HGSC treatment and follow up.

Methods: Our cohort consisted of 122 patients diagnosed with HGSC. Serum samples were collected longitudinally at the time of diagnosis, during treatment and follow up. Serum levels of CA125, CA125-STn and CA125-MGL were determined and compared or correlated with different end points (tumor load assessed intraoperatively, residual disease, treatment response, progression free survival).

Results: Serum CA125-STn levels at diagnosis differentiated patients with low tumor load and high tumor load (p = 0,030), indicating a favorable detection of tumor volume. Similarly, the CA125-STn levels at diagnosis were significantly lower in patients with subsequent complete cytoreduction than in patients with suboptimal cytoreduction (p = 0,025). Conventional CA125 did not differentiate these patients (p = 0,363 and p = 0,154). The CA125-STn nadir value predicted the progression free survival of patients. The detection of disease relapse was improved with CA125-STn, which presented higher fold increase in 80,0% of patients and earlier increase in 37,0% of patients.

Conclusions: CA125-STn showed promise as a useful biomarker in the monitoring and follow up of patients with HGSC utilizing a robust and affordable technique. Our findings are topical as a suitable indicator of tumor load facilitates patient selection in an era of new targeted therapies.
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http://dx.doi.org/10.1016/j.ygyno.2019.12.025DOI Listing
March 2020

Nanoparticle-aided glycovariant assays to bridge biomarker performance and ctDNA results.

Mol Aspects Med 2020 04 29;72:100831. Epub 2019 Nov 29.

Department of Biochemistry/Biotechnology, University of Turku, Turku, Finland. Electronic address:

Numerous immunoassay based cancer biomarkers established in the 1970 and 1980'ies are widely used in clinical routine. Initial expectations of biomarkers such as CEA, CA125, CA19-9, AFP to provide decisive help in the diagnosis of early stage, pre-symptomatic cancers have not been realized. Thus, they are primarily used for monitoring disease progression and occasionally being useful as prognostic indicators. This limitation is due to the marker also being measurable in healthy individuals and frequently at elevated concentrations in common benign conditions. Most conventional tumor markers are glycosylated and interestingly specific alterations of the glycostructure part can often be seen early in the cancerous process. Conventional double monoclonal immunoassays are however blind to such changes as they are based on peptide epitope recognition. Wide selections of carbohydrate recognizing macromolecules, lectins, but also glycan structure recognizing antibodies are potentially useful for detecting such changes. Despite numerous attempts generating proof-of-principle evidence for this, such assays have generally not been successfully introduced into clinical routine. The affinity constants of lectin and glycan specific antibodies for their corresponding carbohydrate structures may be up to several orders too low to provide the detection limits and robustness expected from routine tumor markers. In this review, we describe an approach based on the use of highly fluorescent Eu-chelate dyed nanoparticles onto which lectins or glycan specific antibodies are coated to provide the necessary binding strength and signal amplification to provide low detection limits, while maintaining the original glycan-structure specificity. This concept applied to three markers, PSA, CA125 and CA15-3 provide glycoform assays of greatly enhanced cancer specificity using sample volumes similar or lower than corresponding traditional ELISAs. For ovarian cancer, we show that this new approach when applied to ovarian cyst fluid samples provide results similar to the performance obtained with ctDNA determinations of a set of 17 driver mutations and greatly superior compared to corresponding conventional immunoassays. Based on our results, we predict that the nanoparticle-lectin concept will enable a new generation of simple, low-cost biomarker assays of highly improved cancer specificity. Such tools should ideally be evaluated together with determination of ctDNA to establish early detection schemes for cancers e.g. ovarian, pancreas, lung where the detection rate of early stage disease is presently unacceptably low.
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http://dx.doi.org/10.1016/j.mam.2019.11.001DOI Listing
April 2020

Europium Nanoparticle-Based Sialyl-Tn Monoclonal Antibody Discriminates Epithelial Ovarian Cancer-Associated CA125 from Benign Sources.

J Appl Lab Med 2019 11 23;4(3):299-310. Epub 2019 Aug 23.

Department of Biochemistry/Biotechnology, University of Turku, Turku, Finland.

Background: The Sialyl-Thomsen-nouveau antigen (STn) is abundantly produced on many types of human epithelial cancers including epithelial ovarian cancer (EOC). We previously developed an EOC-specific lectin sandwich immunoassay (CA125) using a human macrophage galactose-binding lectin coated on fluorescent europium nanoparticles (Eu-NPs) as a tracer and an anti-CA125-specific mAb for capture. Here we have identified a novel STn-mAb that efficiently recognizes the EOC-associated STn antigen on CA125 when coated on Eu-NPs.

Method: CA125 from the ovarian cancer cell line OVCAR-3, placental homogenate, and ascites fluid from patients with liver cirrhosis was captured by anti-CA125 antibody immobilized on microtitration wells and traced with anti-STn-mAb-Eu-NPs. Samples from EOC or patients with endometriosis with marginally increased conventional CA125 immunoassay (CA125; 35-200 U/mL) and healthy controls were analyzed.

Results: An analytically sensitive CA125 assay that specifically recognized the CA125 isoform produced by OVCAR-3 was achieved. Serum CA125 concentration was significantly higher in EOC patients than in those with endometriosis ( < 0.001). Furthermore, the sensitivity for detection of EOC with CA125 assay was 73.3% when 95% of endometriosis cases were undetectable.

Conclusion: Our findings suggest that Eu-NPs-based CA125 assay could help reduce the false-positive rates of CA125 to improve differential diagnosis. The results encourage studying further the potential use of CA125 to detect EOC at earlier clinical stages. This approach warrants further investigation in other cancers as well.
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http://dx.doi.org/10.1373/jalm.2018.028266DOI Listing
November 2019

Clinical Utility of Mutant Antibody-Based Assays for Determination of Internally Cleaved and Intact Forms of Free Prostate-Specific Antigen.

J Appl Lab Med 2019 05 1;3(6):1014-1021. Epub 2019 Feb 1.

Departments of Biochemistry/Biotechnology, University of Turku, Turku, Finland.

Background: Subforms of prostate-specific antigen (PSA) have been a subject of intensive research, and use of multikallikrein immunoassays can add clinical value to the early detection of prostate cancer, overcoming known limitations of PSA. In this study, we evaluated mutant 4D4 (L3-2) antibody-assisted assay constructs against reference wild-type (wt)-4D4-based assays for determination of intact PSA (iPSA) and nicked PSA (nPSA) in plasma samples.

Methods: Perioperative plasma samples obtained from 105 men who underwent biopsy (73 cancer, 32 noncancer) were analyzed with sandwich immunoassays for total PSA (tPSA), free PSA (fPSA), iPSA (3 constructs), and measured nPSA (2 constructs). Calculated nPSA (CN) was obtained from total fPSA - iPSA.

Results: Mutant-assisted iPSA assays measured lower concentrations than the reference in both patient groups. CN separated the 2 groups with the iPSA using the mutant for capture (I-MC) performing the best ( = 0.008). In prostate volume group > median, only measured nPSA provided significant discrimination [area under the curve (AUC), 0.71; = 0.016] but equally using mutant and wt antibodies. In the whole cohort, all ratios to tPSA performed well (AUC, 0.819-0.870; ≤ 0.0001) with CN based on I-MC scoring highest (AUC, 0.870). Importantly, in the ≤ median volume group, the I-MC/F and CN(I-MC)/T ratios stand out as the best performing parameters (AUC, 0.825 and 0.861; = 0.001 and = 0.0003, respectively).

Conclusions: The new assay construct using the mutant 4D4 (L3-2) as a capture provides clear improvement in separating cancer from noncancer in all subgroups analyzed but especially in patients with prostate volume ≤ median. ClinicalTrials.gov Identifier NCT01864135.
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http://dx.doi.org/10.1373/jalm.2018.027797DOI Listing
May 2019

Prostate Cancer Risk Stratification in Men With a Clinical Suspicion of Prostate Cancer Using a Unique Biparametric MRI and Expression of 11 Genes in Apparently Benign Tissue: Evaluation Using Machine-Learning Techniques.

J Magn Reson Imaging 2020 05 6;51(5):1540-1553. Epub 2019 Oct 6.

Institute of Biomedicine, University of Turku and Department of Pathology, Turku University Hospital, Turku, Finland.

Background: Accurate risk stratification of men with a clinical suspicion of prostate cancer (cSPCa) remains challenging despite the increasing use of MRI.

Purpose: To evaluate the diagnostic accuracy of a unique biparametric MRI protocol (IMPROD bpMRI) combined with clinical and molecular markers in men with cSPCa.

Study Type: Prospective single-institutional clinical trial (NCT01864135).

Subjects: Eighty men with cSPCa.

Field Strength/sequence: 3T, surface array coils. Two T -weighted and three diffusion-weighted imaging (DWI) acquisitions: 1) b-values 0, 100, 200, 300, 500 s/mm ; 2) b-values 0,1500 s/mm ; 3) b-values 0, 2000 s/mm .

Assessment: IMPROD bpMRI examinations were qualitatively (IMPROD bpMRI Likert score) and quantitatively (DWI-based Gleason grade score) prospectively reported. Men with IMPROD bpMRI Likert 3-5 had two targeted biopsies followed by 12-core systematic biopsies (SB); those with IMPROD bpMRI Likert 1-2 had only SB. Additionally, 2-core from normal-appearing prostate areas were obtained for the mRNA expression of ACSM1, AMACR, CACNA1D, DLX1, PCA3, PLA2G7, RHOU, SPINK1, SPON2, TMPRSS2-ERG, and TDRD1 measured by quantitative reverse-transcription polymerase chain reaction.

Statistical Tests: Univariate and multivariate analysis using regularized least-squares, feature selection and tournament leave-pair-out cross-validation (TLPOCV), as well as 10 random splits of the data in training-testing sets, were used to evaluate the mRNA, clinical and IMPROD bpMRI parameters in detecting clinically significant prostate cancer (SPCa) defined as Gleason score ≥ 3 + 4. The evaluation metric was the area under the curve (AUC).

Results: IMPROD bpMRI Likert demonstrated the highest TLPOCV AUC of 0.92. The tested clinical variables had AUC 0.56-0.73, while the mRNA and additional IMPROD bpMRI parameters had AUC 0.50-0.67 and 0.65-0.89 respectively. The combination of clinical and mRNA biomarkers produced TLPOCV AUC of 0.87, the highest TLPOCV performance without including IMPROD bpMRI Likert.

Data Conclusion: The qualitative IMPROD bpMRI Likert score demonstrated the highest accuracy for SPCa detection compared with the tested clinical variables and mRNA biomarkers.

Level Of Evidence: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1540-1553.
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http://dx.doi.org/10.1002/jmri.26945DOI Listing
May 2020

Cardiac troponin elevations in marathon runners. Role of coronary atherosclerosis and skeletal muscle injury. The MaraCat Study.

Int J Cardiol 2019 11 7;295:25-28. Epub 2019 Aug 7.

Heart Center, Turku University Hospital and University of Turku, Turku, Finland. Electronic address:

Background: Marathon running is associated with transient risk of sudden cardiac death and high cardiac troponin levels are common after race. There is limited data whether coronary atherosclerosis or skeletal muscle injury are related to troponin release caused by strenuous exercise. We aimed to assess whether coronary artery calcification (CAC), plaque vulnerability or skeletal muscle injury relate to cardiac troponin T (cTnT) elevations after marathon race.

Methods: In this observational study, 40 male runners participating in Paavo Nurmi 2018 Marathon were recruited with an open email invitation to evaluate the prevalence of post-race cTnT elevations and their predictors. In addition to baseline and post-race laboratory investigations, 28 runners aged >44 years underwent CAC measurement with computed tomography. Coronary plaque vulnerability was evaluated by free pregnancy-associated plasma protein A (fPAPP-A) concentration and skeletal muscle injury by skeletal troponin I (skTnI) measurement.

Results: The post-marathon cTnT concentrations rose above the normal reference limit in 38 (95%) participants. A 10-fold increase in skTnI concentrations was observed and elevated post-race values were seen in all participants. The correlation between the post-race cTnT and post-race skTnI (r = -0.26, p = 0.11) was non-significant. CAC was detected (Agatston score > 0) in 15 (53.6%) participants, with a median score of 2.0 (interquartile range [IQR] 80). There was no correlation between cTnT with CAC score or post-race fPAPP-A levels.

Conclusions: Asymptomatic cardiac troponin elevations are common after prolonged strenuous exercise, but are not related to markers of coronary atherosclerosis, plaque vulnerability or skeletal muscle injury.
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http://dx.doi.org/10.1016/j.ijcard.2019.08.019DOI Listing
November 2019

Lectin nanoparticle assays for detecting breast cancer-associated glycovariants of cancer antigen 15-3 (CA15-3) in human plasma.

PLoS One 2019 25;14(7):e0219480. Epub 2019 Jul 25.

Department of Biochemistry/Biotechnology, University of Turku, Turku, Finland.

Cancer antigen 15-3 (CA15-3) is widely utilized for monitoring metastatic breast cancer (BC). However, its utility for early detection of breast cancer is severely limited due to poor clinical sensitivity and specificity. The glycosylation of CA15-3 is known to be affected by BC, and therefore it might offer a way to construct CA15-3 glycovariant assays with improved cancer specificity. To this end, we performed lectin-based glycoprofiling of BC-associated CA15-3. CA15-3 expressed by a BC cell line was immobilized on microtitration wells using an anti-CA15-3 antibody. The glycosylation of the immobilized CA15-3 was then detected by using lectins coated onto europium (III)-doped nanoparticles (Eu+3-NPs) and measuring the time-resolved fluorescence of Eu. Out of multiple lectin-Eu+3-NP preparations, wheat germ agglutinin (WGA) and macrophage galactose-type lectin (MGL) -Eu3+-NPs bound to the BC cell line-dericed CA15-3 glycovariants (CA15-3Lectin). To evaluate the clinical performance of these two lectin-based assays, plasma samples from metastatic BC patients (n = 53) and healthy age-matched women (n = 20).Plasma CA15-3Lectin measurements better distinguished metastatic BC patients from healthy controls than the conventional CA15-3 immunoassay. At 90% specificity, the clinical sensitivity of the assays was 66.0, 67.9 and 81.1% for the conventional CA15-3, CA15-3MGL and CA15-3WGA assays, respectively. Baseline CA15-3MGL and CA15-3WGA were correlated to conventional baseline CA15-3 levels (r = 0.68, p<0.001, r = 0.90, p>0.001, respectively). However, very low baseline CA15-3MGL levels ≤ 5 U/mL were common in this metastatic breast cancer patient population.In conclusion, the new CA15-3Lectin concept could considerably improve the clinical sensitivity of BC detection compared to the conventional CA15-3 immunoassays and should be validated further on a larger series of subjects with different cancer subtypes and stages.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0219480PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6658058PMC
February 2020

A Nanoparticle-Based Approach for the Detection of Extracellular Vesicles.

Sci Rep 2019 07 11;9(1):10038. Epub 2019 Jul 11.

Department of Biochemistry, Division of Biotechnology, University of Turku, Turku, Finland.

The analysis of extracellular vesicles (EVs) typically requires tedious and time-consuming isolation process from bio-fluids. We developed a nanoparticle-based time resolved fluorescence immunoassay (NP-TRFIA) that uses biotinylated antibodies against the proteins of tetraspanin family and tumor-associated antigens for capturing EVs from urine samples and cell culture supernatants without the need for isolation. The captured-EVs were detected either with Eu-chelate or Eu-doped nanoparticle-based labels conjugated either to antibodies against the tetraspanins or lectins targeting the glycan moieties on EVs surface. The NP-TRFIA demonstrated specific capturing and detection of EVs by antibodies and lectins. Lectin-nanoparticle based assays showed 2-10 fold higher signal-to-background ratio compared with lectin-chelate assays. The nanoparticle assay concept allowed surface glycosylation profiling of the urine derived-EVs with lectins. It was also applied to establish an assay showing differential expression of tumor-associated proteins on more aggressive (higher ITGA3 on DU145- and PC3-EVs) compared to less aggressive (higher EpCAM on LNCaP-EVs) PCa- cell lines derived-EVs. This NP-TRFIA can be used as a simple tool for analysis and characterization of EVs in urine and cell culture supernatants. Such approach could be useful in identification of disease-specific markers on the surface of patient-derived urinary EVs.
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http://dx.doi.org/10.1038/s41598-019-46395-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6624270PMC
July 2019

Development of anti-immunocomplex specific antibodies and non-competitive time-resolved fluorescence immunoassay for the detection of estradiol.

Anal Bioanal Chem 2019 Sep 8;411(22):5633-5639. Epub 2019 Jun 8.

Department of Biochemistry, University of Turku, Kiinanmyllynkatu 10, 20520, Turku, Finland.

Detection of circulatory estradiol has widespread use in various clinical applications. Particularly, the use of estradiol-specific antibodies in immunoassays is routinely used, mainly due to the cost efficiency and simplicity of the sample handling process. However, the circulatory levels of estradiol can be extremely low in some conditions, and beyond the current detection limit of existing competitive immunoassays. We describe the generation of anti-immunocomplex specific antibodies derived from synthetic antibody repertoire and the development of high-performance non-competitive immunoassay for the detection of estradiol. Phage display selections were used to isolate new antibodies from synthetic antibody library with the use of existing estradiol specific Fab fragment. The found antibodies were consecutively used to set up a time-resolved fluorescence-based immunoassay (TRFIA), which can be used to detect estradiol with exceptional sensitivity and specificity. The limit of detection and EC50 were shown to be 3.0 pg mL and 32.4 pg mL respectively. Graphical abstract.
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http://dx.doi.org/10.1007/s00216-019-01952-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6704259PMC
September 2019

High-sensitivity lateral flow immunoassay with a fluorescent lanthanide nanoparticle label.

J Immunol Methods 2019 02 4;465:39-44. Epub 2018 Dec 4.

Department of Biotechnology, University of Turku, Turku, Finland.

Lateral flow (LF) immunoassays are commonly used for point-of-care testing and typically incorporate visually read reporters, such as gold particles. To improve sensitivity and develop quantitative LF immunoassays, visual reporters can be replaced by fluorescent reporters detected by an instrument. In this study, we used fluorescent europium(III) chelate doped nanoparticle (Eu-np) reporters to develop a quantitative high-sensitivity LF immunoassay for free prostate specific antigen (fPSA). Furthermore, we tested different simplified formats of the assay and the effect of different modifiable parameters on the detection limit of the assay: dynamic range, assay duration and number of assay steps. The molar detection limits of the different assay formats were compared with published detection limits of LF immunoassays with different reporters. The cutoff was calculated from 11 female serum samples. The detection limit of the sensitivity optimized fPSA assay with fPSA spiked into pooled female serum was 0.01 ng/ml, which is approximately 100-fold lower than the most sensitive gold particle LF assays and 10-fold lower than other Eu-np and carbon nanoparticle based LF immunoassays. Thus, Eu-np reporters can be used to develop highly sensitive and quantitative LF immunoassays.
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http://dx.doi.org/10.1016/j.jim.2018.12.001DOI Listing
February 2019

Free PAPP-A as a biomarker: heparin-induced release is not related to coronary atherosclerotic burden.

Clin Chem Lab Med 2019 06;57(7):e155-e158

Turku PET Centre and Heart Center, University of Turku and Turku University Hospital, Turku, Finland.

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http://dx.doi.org/10.1515/cclm-2018-1062DOI Listing
June 2019

Direct Immunoassay for Free Pregnancy-Associated Plasma Protein A (PAPP-A).

J Appl Lab Med 2018 Nov;3(3):438-449

Department of Biochemistry/Biotechnology, University of Turku, Turku, Finland.

Background: Pregnancy-associated plasma protein A (PAPP-A), especially in its noncomplexed form (fPAPP-A), is linked to vulnerable atherosclerotic plaques and risk of cardiac events. An assay for sensitive detection of fPAPP-A has been lacking. Our aim was to develop and validate a direct fPAPP-A assay to meet this need.

Methods: Monoclonal antibodies binding exclusively fPAPP-A were produced by immunizing mice with recombinant PAPP-A. In the optimized immunoassay, we used an fPAPP-A-specific capture antibody together with a lanthanide-chelate-labeled monoclonal antibody recognizing all PAPP-A forms. The assay was evaluated with CLSI guidelines and compared to a 2-assay subtractive fPAPP-A approach. Clinical performance was assessed with acute coronary syndrome patients.

Results: The limits of detection and quantitation were 0.4 mIU/L and 1.3 mIU/L, respectively, and the assay was linear up to 1000 mIU/L (R2 = 0.999). Both serum and heparin plasma were suitable matrices, and the complexed form of PAPP-A caused no significant interference. Correlation between the developed assay and the 2-assay approach was fair (Pearson's r = 0.819). Median concentration in healthy individuals was 1.0 mIU/L. fPAPP-A concentration was higher in patients who had myocardial infarction or died during the 1-year follow-up period than in those who did not (1.13 mIU/L vs 0.82 mIU/L, P = 0.008, model adjusted with age and sex). fPAPP-A measured with this direct assay predicted this end point as well as (follow-up 1 year) or better (30 days) than the 2-assay fPAPP-A alone or in combination with cTnI.

Conclusions: The new assay enables sensitive and reliable measurement of low cardiac-related fPAPP-A concentrations from blood samples.
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http://dx.doi.org/10.1373/jalm.2018.026096DOI Listing
November 2018

Microparticle-based platform for point-of-care immunoassays.

Anal Biochem 2018 05 24;548:66-68. Epub 2018 Feb 24.

Department of Biotechnology, University of Turku, Turku, Finland.

There is a need for quantitative and sensitive, yet simple point-of-care immunoassays. We have developed a point-of-care microparticle-based immunoassay platform which combines the performance of a microtiter well-based assay with the usability of a rapid assay. The platform contained a separate reaction and detection chambers and microparticles for the solid-phase. Photoluminescent up-converting nanoparticles (UCNPs) were used as labels. The platform was tested with a cardiac troponin I assay, and a limit of detection of 19.7 ng/L was obtained. This study demonstrates the feasibility of developing point-of-care assays on the new platform for various analytes of interests.
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http://dx.doi.org/10.1016/j.ab.2018.02.021DOI Listing
May 2018

A randomized trial of early detection of clinically significant prostate cancer (ProScreen): study design and rationale.

Eur J Epidemiol 2017 06 31;32(6):521-527. Epub 2017 Jul 31.

Department of Urology, Faculty of Medicine and Life Sciences, Tampere University Hospital, University of Tampere, Tampere, Finland.

The current evidence of PSA-based prostate cancer screening shows a reduction in cause-specific mortality, but with substantial overdiagnosis. Recently, new developments in detection of clinically relevant prostate cancer include multiple kallikreins as biomarkers besides PSA, and multiparametric magnetic resonance imaging (mpMRI) for biopsy decision. They offer opportunities for improving the outcomes in screening, particularly reduction in overdiagnosis and higher specificity for potentially lethal cancer. A population-based randomized screening trial will be started, with 67,000 men aged 55-67 years at entry. A quarter of the men will be allocated to the intervention arm, and invited to screening. The control arm will receive no intervention. All men in the screening arm will be offered a serum PSA determination. Those with PSA of 3 ng/ml or higher will have an additional multi-kallikrein panel and those with indications of increased risk of clinically relevant prostate cancer will undergo mpMRI. Men with a malignancy-suspect finding in MRI are referred to targeted biopsies. Screening interval is 6 years for men with baseline PSA < 1.5 ng/ml, 4 years with PSA 1.5-3.0 and 2 years if initial PSA > 3. The main outcome of the trial is prostate cancer mortality, with analysis at 10 and 15 years. The statistical power is sufficient for detecting a 28% reduction at 10 years and 22% at 15 years. The proposed study has the potential to provide the evidence to justify screening as a public health policy if mortality benefit can be sustained with substantially reduced overdiagnosis.
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http://dx.doi.org/10.1007/s10654-017-0292-5DOI Listing
June 2017

Potentially pathogenic circulating autoantibodies to cardiac troponin are present in hemodialysis patients.

Hemodial Int 2017 10 20;21(4):519-523. Epub 2016 Nov 20.

Department of Renal Medicine, Royal Derby Hospital, UK.

Introduction: Repetitive dialysis-induced cardiac injury is associated with elevated troponin levels, inflammation, and longitudinal reduction in cardiac function. Pathogenic autoantibodies to cardiac troponins (cTnAAb) produce inflammatory cardiomyopathy in murine models. This study aimed to explore the possibility that analogous autoimmune processes might occur in hemodialysis (HD) patients, by initially investigating cTnAAb prevalence, and exploring potential links with HD-induced myocardial stunning.

Methods: In 130 prevalent HD patients from two centers (Derby, UK; Turku, Finland), cTnAAb (immunoassay) and cardiac troponins were quantified. Sixty-four patients underwent serial echocardiography to assess myocardial stunning.

Findings: cTnAAb were present in 7% of patients. Dual positivity to cTnAAb and elevated cTn occurred in 3% and 6% for cTnI and cTnT, respectively. Patients with cTnAAb had significantly longer dialysis vintage (82 vs. 30 months, P = 0.024), higher cTnT (0.1 vs. 0.05 pg/mL, P = 0.04), cTnI (0.02 vs. 0.01 pg/mL, P = 0.029), and free PAPP-A (6.4 vs. 3.3 mIU/L, P = 0.038).

Discussion: This is the first description of cTnAAb in HD patients, which raises the possibility that longitudinal exposure to repetitive HD-induced cardiac injury may lead to further autoimmune-based myocardial insult.
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http://dx.doi.org/10.1111/hdi.12514DOI Listing
October 2017

Improved cancer specificity in PSA assay using Aleuria aurantia lectin coated Eu-nanoparticles for detection.

Clin Biochem 2017 Jan 4;50(1-2):54-61. Epub 2016 Nov 4.

Department of Biochemistry-Biotechnology, University of Turku, Turku, Finland.

Objectives: The objective was to study the differences in PSA fucosylation obtained from LNCaP and PC-3 prostate cancer cell lines, seminal plasma PSA and recombinant precursor form of PSA expressed in baculovirus, using Aleuria aurantia lectin (AAL). The aim was to assess whether differences in fucosylation (Fucα1-6/3GlcNAc carbohydrates) of PSA either in urine, blood or tissue enable the discrimination of patients with prostate cancer (PCa) from benign prostatic hyperplasia (BPH) and young males.

Design And Methods: Two novel lectin-immunoassays were developed for the analysis of fucosylation of PSA by measuring the time-resolved fluorescence of europium chelate. The lectin-immunoassays utilize free PSA-specific Fab-fragments for capturing the analyte and either europium-labeled AAL or AAL coupled to Eu(III)-chelate-dyed nanoparticles for the detection of Fucα1-6/3GlcNAc carbohydrates on PSA.

Results: Using the novel lectin-immunoassays, we showed higher levels of Fucα1-6/3GlcNAc on PSA derived from LNCaP and PC-3 cells compared to seminal plasma PSA. With the more sensitive nanoparticle-based lectin-immunoassay we detected a statistically significant increase in the PSA fucosylation in PCa tissue compared to benign tissue (p=0.001) and in urine from PCa patients compared to BPH patients (p=0.030), and an even greater discrimination (p=0.010) when comparing BPH patients to PCa patients with Gleason score≥7.

Conclusions: AAL coupled to Eu(III)-chelate-dyed nanoparticles improved the sensitivity of immunoassay for the detection of Fucα1-6/3GlcNAc structures on PSA. The preliminary findings show an increased fucosylation in PCa compared to benign conditions. Further validation is required to assess the true clinical utility of AAL in PCa diagnosis.
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http://dx.doi.org/10.1016/j.clinbiochem.2016.06.015DOI Listing
January 2017

Lateral flow immunoassay with upconverting nanoparticle-based detection for indirect measurement of interferon response by the level of MxA.

J Med Virol 2017 04 27;89(4):598-605. Epub 2016 Sep 27.

Department of Virology, University of Turku, Turku, Finland.

Myxovirus resistance protein A (MxA) is a biomarker of interferon-induced gene expression state involved in many viral infections and some autoimmune disorders. It has a variety of potential utilities in clinical diagnostics, including distinguishing between bacterial and viral infections. Currently, MxA-assays are used for monitoring of IFN-β therapy in multiple sclerosis (MS) patients. As a proof-of-concept for rapid quantitative measurement of interferon response, a lateral flow immunoassay (LFIA) with upconverting nanoparticle (UCNP) reporters was developed and evaluated with clinical whole blood samples to assess the potential for a rapid and user-friendly quantitative assay for MxA, since the currently available rapid test for MxA (FebriDX) produces only qualitative result. The high detection sensitivity enabled by the UCNP reporter technology allowed the sample pre-treatment with dilution of whole blood into lysis buffer at a detectable analyte concentration. The assay can be done within 2 hr and the results correlate with the reference MxA-ELISA, which requires an overnight incubation. With 36 samples, R for linear regression was 0.86. The assay detected 96% of the IFN-β responders with 89% specificity using a cut-off level of 100 μg/L for an elevated MxA-concentration. J. Med. Virol. 89:598-605, 2017. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jmv.24689DOI Listing
April 2017

A Nanoparticle-Lectin Immunoassay Improves Discrimination of Serum CA125 from Malignant and Benign Sources.

Clin Chem 2016 10 18;62(10):1390-400. Epub 2016 Aug 18.

Department of Biochemistry/Biotechnology, University of Turku, Turku, Finland;

Background: Measurement of serum cancer antigen 125 (CA125) is the standard approach for epithelial ovarian cancer (EOC) diagnostics and follow-up. However, the clinical specificity is not optimal because increased values are also detected in healthy controls and in benign diseases. CA125 is known to be differentially glycosylated in EOC, potentially offering a way to construct CA125 assays with improved cancer specificity. Our goal was to identify carbohydrate-reactive lectins for discriminating between CA125 originating from EOC and noncancerous sources.

Methods: CA125 from the OVCAR-3 cancer cell line, placental homogenate, and ascites fluid from patients with cirrhosis were captured on anti-CA125 antibody immobilized on microtitration wells. A panel of lectins, each coated onto fluorescent europium-chelate-doped 97-nm nanoparticles (Eu(+3)-NPs), was tested for detection of the immobilized CA125. Serum samples from high-grade serous EOC or patients with endometriosis and healthy controls were analyzed.

Results: By using macrophage galactose-type lectin (MGL)-coated Eu(+3)-NPs, an analytically sensitive CA125 assay (CA125(MGL)) was achieved that specifically recognized the CA125 isoform produced by EOC, whereas the recognition of CA125 from nonmalignant conditions was reduced. Serum CA125(MGL) measurement better discriminated patients with EOC from endometriosis compared to conventional immunoassay. The discrimination was particularly improved for marginally increased CA125 values and for earlier detection of EOC progression.

Conclusions: The new CA125(MGL) assay concept could help reduce the false-positive rates of conventional CA125 immunoassays. The improved analytical specificity of this test approach is dependent on a discriminating lectin immobilized in large numbers on Eu(+3)-NPs, providing both an avidity effect and signal amplification.
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http://dx.doi.org/10.1373/clinchem.2016.257691DOI Listing
October 2016