Repository logo
 

BRCA1-like signature in triple negative breast cancer: Molecular and clinical characterization reveals subgroups with therapeutic potential.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Severson, Tesa M 
Peeters, Justine 
Majewski, Ian 
Michaut, Magali 
Bosma, Astrid 

Abstract

Triple negative (TN) breast cancers make up some 15% of all breast cancers. Approximately 10-15% are mutant for the tumor suppressor, BRCA1. BRCA1 is required for homologous recombination-mediated DNA repair and deficiency results in genomic instability. BRCA1-mutated tumors have a specific pattern of genomic copy number aberrations that can be used to classify tumors as BRCA1-like or non-BRCA1-like. BRCA1 mutation, promoter methylation, BRCA1-like status and genome-wide expression data was determined for 112 TN breast cancer samples with long-term follow-up. Mutation status for 21 known DNA repair genes and PIK3CA was assessed. Gene expression and mutation frequency in BRCA1-like and non-BRCA1-like tumors were compared. Multivariate survival analysis was performed using the Cox proportional hazards model. BRCA1 germline mutation was identified in 10% of patients and 15% of tumors were BRCA1 promoter methylated. Fifty-five percent of tumors classified as BRCA1-like. The functions of genes significantly up-regulated in BRCA1-like tumors included cell cycle and DNA recombination and repair. TP53 was found to be frequently mutated in BRCA1-like (P < 0.05), while PIK3CA was frequently mutated in non-BRCA1-like tumors (P < 0.05). A significant association with worse prognosis was evident for patients with BRCA1-like tumors (adjusted HR = 3.32, 95% CI = 1.30-8.48, P = 0.01). TN tumors can be further divided into two major subgroups, BRCA1-like and non-BRCA1-like with different mutation and expression patterns and prognoses. Based on these molecular patterns, subgroups may be more sensitive to specific targeted agents such as PI3K or PARP inhibitors.

Description

Keywords

BRCA1, Breast cancer, Genomic instability, Targeted therapy, Triple negative breast cancer, Adult, Aged, Aged, 80 and over, Comparative Genomic Hybridization, DNA Methylation, DNA Mutational Analysis, Female, Gene Expression Profiling, Gene Expression Regulation, Neoplastic, Genes, BRCA1, High-Throughput Nucleotide Sequencing, Humans, Microarray Analysis, Middle Aged, Molecular Targeted Therapy, Promoter Regions, Genetic, Transcriptome, Triple Negative Breast Neoplasms

Journal Title

Mol Oncol

Conference Name

Journal ISSN

1574-7891
1878-0261

Volume Title

9

Publisher

Wiley
Sponsorship
European Commission (258967)
Cancer Research UK (16942)