Copy-number and targeted sequencing analyses to identify distinct prognostic groups: Implications for patient selection to targeted therapies amongst anti-endocrine therapy resistant early breast cancers.

Authors

null

Jane Bayani

Ontario Institute for Cancer Research, Toronto, ON, Canada

Jane Bayani , Elizabeth Kornaga , Cheryl Crozier , Gun Ho Jang , Irina Kalatskaya , Quang M Trinh , Cindy Q Yao , Julie Livingstone , Annette Hasenburg , Dirk G Kieback , Christos Markopoulos , Luc Dirix , Paul Christopher Boutros , Melanie Spears , Lincoln D. Stein , Daniel Rea , John Bartlett

Organizations

Ontario Institute for Cancer Research, Toronto, ON, Canada, University of Mainz, Mainz, Germany, Helios Medical Center, Schleswig, Germany, Hellenic Cooperative Oncology Group (HeCOG), Athens, Greece, Sint-Augustinus Hospital Oncology Center, Medical Oncology, Antwerpen, Belgium, University of Toronto, Toronto, ON, Canada, Cancer Research UK Institute for Cancer Studies, Birmingham, United Kingdom

Research Funding

Other

Background: Hormone receptor positive breast cancer is a therapeutic challenge. Despite optimal anti-endocrine therapies, most breast cancer deaths follow a diagnosis of early luminal cancer. To understand the impact of multiple aberrations in the context of current therapy, we assessed the prognostic ability of genomic signatures as a putative stratification tool to targeted therapies. Methods: This a priori study is based on molecular pathways which might predict response to targeted therapies. DNA from 420 patients from the phase III TEAM pathology cohort were used. Patients with a distant recurrence within 5 years were matched by clinical variables to those disease-free at follow up. Copy number analysis was performed using the Affymetrix Oncoscan Assay. Targeted sequencing was performed in a subset of samples for genes based on signaling cassettes mined from the ICGC. Pathways were identified as aberrant if there were copy number variations (CNVs) and/or mutations in any of the pre-determined pathway genes: 1) CCND1/CCND2/CCND3/CDK4/CDK6; 2) FGFR1/FGFR2/FGFR2/FGFR4; and 3) AKT1/AKT2/PIK3CA/PTEN. Kaplan-Meier and log-rank analyses were used for DFS between groups. Hazard ratios were calculated using the Cox proportional hazard models adjusted for age, tumour size, grade, lymph node and HER2 status. Results: 390/420 samples passed informatics QC filters. For the CCND/CDK pathway, patients with no CNV changes experienced a better DFS (HR = 1.7, 95% CI 1.3-2.3, p < 0.001). For the FGFR/FGF pathway, a similar outcome is seen among patients without CNVs (HR = 1.5, 95% CI 1.1-2.0; p = 0.005). For AKT/PIK3CA, a decrease in DFS was seen in those with aberrations (HR = 1.4, 95% CI 1.0-1.8, p = 0.03). Conclusions: We demonstrated that CNVs of genes within CDK4/CCND, PIK3CA/AKT and FGFR pathways are independently linked to high risk of relapse following endocrine treatment, with implications for identifying those patients who are at high-risk for recurrence despite optimal anti-endocrine therapy and linking molecular features driving these cancers to targeted therapies.

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Abstract Details

Meeting

2017 ASCO Annual Meeting

Session Type

Poster Session

Session Title

Breast Cancer—Local/Regional/Adjuvant

Track

Breast Cancer

Sub Track

Adjuvant Therapy

Citation

J Clin Oncol 35, 2017 (suppl; abstr 524)

DOI

10.1200/JCO.2017.35.15_suppl.524

Abstract #

524

Poster Bd #

124

Abstract Disclosures

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