Publications by authors named "Jose Buleje"

5 Publications

  • Page 1 of 1

PUM1 and RNase P genes as potential cell-free DNA markers in breast cancer.

J Clin Lab Anal 2021 Apr 1;35(4):e23720. Epub 2021 Feb 1.

Facultad de Medicina Humana, Centro de Investigación de Genética y Biología Molecular, Instituto de Investigación, Universidad de San Martín de Porres, Lima, Perú.

Background: Cell-free DNA (cfDNA) is used in clinical research to identify biomarkers for diagnosis of and follow-up on cancer. Here, we propose a fast and innovative approach using traditional housekeeping genes as cfDNA targets in a copy number analysis. We focus on the application of highly sensitive technology such as digital PCR (dPCR) to differentiate breast cancer (BC) patients and controls by quantifying regions of PUM1 and RPPH1 (RNase P) in plasma samples.

Methods: We conducted a case-control study with 82 BC patients and 82 healthy women. cfDNA was isolated from plasma using magnetic beads and quantified by spectrophotometry to estimate total cfDNA. Then, both PUM1 and RPPH1 genes were specifically quantified by dPCR. Data analysis was calibrated using a reference genomic DNA in different concentrations.

Results: We found RNase P and PUM1 values were correlated in the patient group (intraclass correlation coefficient [ICC] = 0.842), but they did not have any correlation in healthy women (ICC = 0.519). In dPCR quantification, PUM1 showed the capacity to distinguish early-stage patients and controls with good specificity (98.67%) and sensitivity (100%). Conversely, RNase P had lower cfDNA levels in triple-negative BC patients than luminal subtypes (p < 0.025 for both), confirming their utility for patient classification.

Conclusion: We propose the PUM1 gene as a cfDNA marker for early diagnosis of BC and RNase P as a cfDNA marker related to hormonal status and subtype classification in BC. Further studies with larger sample sizes are warranted.
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April 2021

A snapshot of current genetic testing practice in Lynch syndrome: The results of a representative survey of 33 Latin American existing centres/registries.

Eur J Cancer 2019 09 20;119:112-121. Epub 2019 Aug 20.

Hospital de Especialidades Eugenio Espejo, Subproceso de Anatomía Patológica, Área de Genética Clínica, Quito, Ecuador.

We aimed to assess the current genetics practice to manage patients with Lynch syndrome (LS) across Latin America. A Latin American LS survey was sent out to 52 centres/registries, comprising a total of 12 countries from the region. Overall, 33 centres completed the survey, of which the oldest LS registry was established in 1992 in Sao Paulo (Brazil), and the youngest this year in San Jose (Costa Rica). In total, 87% (26/30) of the participating centres/registries belonging to the nine countries are performing genetic testing. Overall, 1352 suspected families were sequenced. Pathogenic variants were identified in 34% of the families, with slightly differing distribution of variants between females and males. Path_MLH1 variants were identified in 39% of females and 50% of males (p = 0.023), while path_MSH2 were identified in 37% of females and males, followed by path_PMS2 in 11% of females and 8% of males, path_MSH6 in 13% of females and 3% of males (p < 0.001) and path_EPCAM in 0.3% of females and 2% of males. In Latin America, 9 of 12 (75%) participating countries had implemented healthcare for LS. LS screening is inconsistently applied within Latin America healthcare systems because of structural differences in the healthcare systems between the countries.
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September 2019

From colorectal cancer pattern to the characterization of individuals at risk: Picture for genetic research in Latin America.

Int J Cancer 2019 07 5;145(2):318-326. Epub 2018 Dec 5.

AC Camargo Cancer Center, Sao Paulo, Brazil.

Colorectal cancer (CRC) is one of the most common cancers in Latin America and the Caribbean, with the highest rates reported for Uruguay, Brazil and Argentina. We provide a global snapshot of the CRC patterns, how screening is performed, and compared/contrasted to the genetic profile of Lynch syndrome (LS) in the region. From the literature, we find that only nine (20%) of the Latin America and the Caribbean countries have developed guidelines for early detection of CRC, and also with a low adherence. We describe a genetic profile of LS, including a total of 2,685 suspected families, where confirmed LS ranged from 8% in Uruguay and Argentina to 60% in Peru. Among confirmed LS, path_MLH1 variants were most commonly identified in Peru (82%), Mexico (80%), Chile (60%), and path_MSH2/EPCAM variants were most frequently identified in Colombia (80%) and Argentina (47%). Path_MSH6 and path_PMS2 variants were less common, but they showed important presence in Brazil (15%) and Chile (10%), respectively. Important differences exist at identifying LS families in Latin American countries, where the spectrum of path_MLH1 and path_MSH2 variants are those most frequently identified. Our findings have an impact on the evaluation of the patients and their relatives at risk for LS, derived from the gene affected. Although the awareness of hereditary cancer and genetic testing has improved in the last decade, it is remains deficient, with 39%-80% of the families not being identified for LS among those who actually met both the clinical criteria for LS and showed MMR deficiency.
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July 2019

Mutational analysis of and genes in Peruvian families with hereditary breast and ovarian cancer.

Mol Genet Genomic Med 2017 Sep 28;5(5):481-494. Epub 2017 Jun 28.

Centro de Genética y Biología MolecularFacultad de Medicina HumanaUniversidad de San Martín de PorresLimaPerú.

Background: Breast cancer is one of the most prevalent malignancies in the world. In Peru, breast cancer is the second cause of death among women. Five to ten percent of patients present a high genetic predisposition due to and germline mutations.

Methods: We performed a comprehensive analysis of and genes by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) to detect large rearrangements in patients from 18 families, which met the criteria for hereditary breast cancer.

Results: In this series, we found four pathogenic mutations, three previously reported (: c.302-1G>C and c.815_824dup10; : c.5946delT) and a duplication of adenines in exon 15 in gene (c.4647_4648dupAA, ClinVar SCV000256598.1). We also found two exonic and four intronic variants of unknown significance and 28 polymorphic variants.

Conclusion: This is the first report to determine the spectrum of mutations in the genes in Peruvian families selected by clinical and genetic criteria. The alteration rate in with proven pathogenic mutation was 22.2% (4 out 18) and this finding could be influenced by the reduced sample size or clinical criteria. In addition, we found three known mutations and a c.4647_4648dupAA as a novel pathogenic mutation.
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September 2017

Mutational profile of KIT and PDGFRA genes in gastrointestinal stromal tumors in Peruvian samples.

Rev Esp Enferm Dig 2015 Feb;107(2):72-8

Introduction: Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms usually caused by somatic mutations in the genes KIT (c-kit) or PDGFRA. Mutation characterization has become an important exam for GIST patients because it is useful in predicting the response to the inhibitors of receptor tyrosine kinase (RTK).

Objectives: The aim of this study was to determine the frequency of KIT and PDGFRA mutations in 25 GIST samples collected over two years at two national reference hospitals in Peru. There were 21 samples collected from the Instituto Nacional de Enfermedades Neoplásicas (INEN, national cancer center) and 4 samples collected from Hospital A. Loayza.

Methods And Materials: In this retrospective study, we performed polymerase chain reaction (PCR) amplification and deoxyribonucleic acid (DNA) sequencing of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes in 20 FFPE (formalin-fixed, paraffin-embedded) and 5 frozen GIST samples.

Results: We report 21 mutations, including deletions, duplications, and missense, no mutations in 2 samples, and 2 samples with no useful DNA for further analysis. Eighty-six percent of these mutations were located in exon 11 of KIT, and 14 % were located in exon 18 of PDGFRA.

Conclusions: Our study identified mutations in 21 out of 25 GIST samples from 2 referential national hospitals in Peru, and the mutation proportion follows a global tendency observed from previous studies (i.e., the majority of samples presented KIT mutations followed by a minor percentage of PDGFRA mutations). This study presents the first mutation data of the KIT and PDGFRA genes from Peruvian individuals with GIST.
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February 2015