Publications by authors named "Maxwell R Lloyd"

3 Publications

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Genomic Characterization of Metastatic Breast Cancer.

Clin Cancer Res 2021 Feb 8;27(4):1105-1118. Epub 2020 Dec 8.

Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.

Purpose: In contrast to recurrence after initial diagnosis of stage I-III breast cancer [recurrent metastatic breast cancer (rMBC)], metastatic breast cancer (dnMBC) represents a unique setting to elucidate metastatic drivers in the absence of treatment selection. We present the genomic landscape of dnMBC and association with overall survival (OS).

Experimental Design: Targeted DNA sequencing (OncoPanel) was prospectively performed on either primary or metastatic tumors from 926 patients (212 dnMBC and 714 rMBC). Single-nucleotide variants, copy-number variations, and tumor mutational burden (TMB) in treatment-naïve dnMBC primary tumors were compared with primary tumors in patients who ultimately developed rMBC, and correlated with OS across all dnMBC.

Results: When comparing primary tumors by subtype, amplification was enriched in triple-negative dnMBC versus rMBC (21.1% vs. 0%, = 0.0005, = 0.111). Mutations in , and were more prevalent, and and less prevalent, in primary HR/HER2 tumors of dnMBC versus rMBC, though not significant after multiple comparison adjustment. Alterations associated with shorter OS in dnMBC included TP53 (wild-type: 79.7 months; altered: 44.2 months; = 0.008, = 0.107), MYC (79.7 vs. 23.3 months; = 0.0003, = 0.011), and cell-cycle (122.7 vs. 54.9 months; = 0.034, = 0.245) pathway genes. High TMB correlated with better OS in triple-negative dnMBC ( = 0.041).

Conclusions: Genomic differences between treatment-naïve dnMBC and primary tumors of patients who developed rMBC may provide insight into mechanisms underlying metastatic potential and differential therapeutic sensitivity in dnMBC. Alterations associated with poor OS in dnMBC highlight the need for novel approaches to overcome potential intrinsic resistance to current treatments.
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February 2021

The Genomic Landscape of Intrinsic and Acquired Resistance to Cyclin-Dependent Kinase 4/6 Inhibitors in Patients with Hormone Receptor-Positive Metastatic Breast Cancer.

Cancer Discov 2020 Aug 13;10(8):1174-1193. Epub 2020 May 13.

Center for Cancer Precision Medicine, Dana-Farber Cancer Institute, Boston, Massachusetts.

Mechanisms driving resistance to cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in hormone receptor-positive (HR) breast cancer have not been clearly defined. Whole-exome sequencing of 59 tumors with CDK4/6i exposure revealed multiple candidate resistance mechanisms including loss, activating alterations in , and , and loss of estrogen receptor expression. experiments confirmed that these alterations conferred CDK4/6i resistance. Cancer cells cultured to resistance with CDK4/6i also acquired , or alterations, which conferred sensitivity to AURKA, ERK, or CHEK1 inhibition. Three of these activating alterations-in , and -have not, to our knowledge, been previously demonstrated as mechanisms of resistance to CDK4/6i in breast cancer preclinically or in patient samples. Together, these eight mechanisms were present in 66% of resistant tumors profiled and may define therapeutic opportunities in patients. SIGNIFICANCE: We identified eight distinct mechanisms of resistance to CDK4/6i present in 66% of resistant tumors profiled. Most of these have a therapeutic strategy to overcome or prevent resistance in these tumors. Taken together, these findings have critical implications related to the potential utility of precision-based approaches to overcome resistance in many patients with HR metastatic breast cancer..
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August 2020