Alterations in Homologous Recombination-Related Genes and Distinct Platinum Response in Metastatic Triple-Negative Breast Cancers: A Subgroup Analysis of the ProfiLER-01 Trial
Elise Bonnet, Véronique Haddad, Stanislas Quesada, Kim-Arthur Baffert, Audrey Lardy-Cléaud, Isabelle Treilleux, Daniel Pissaloux, Valéry Attignon, Qing Wang, Adrien Buisson, Pierre‐Etienne Heudel, Thomas Bachelot, Armelle Dufresne, Lauriane Eberst, Philippe Toussaint, Valérie Bonadona, Christine Lasset, Alain Viari, Emilie Sohier, Sandrine Paindavoine, Valérie Combaret, David Pérol, Isabelle Ray‐Coquard, Jean‐Yves Blay, Olivier Trédan
Abstract
Background: a specific subset of metastatic triple-negative breast cancers (mTNBC) is characterized by homologous recombination deficiency (HRD), leading to enhanced sensitivity to platinum-based chemotherapy. Apart from mutations in BRCA1/2 genes, the evaluation of other HRD-related alterations has been limited to date. As such, we analyzed data from mTNBC patients enrolled in the ProfiLER-01 study to determine the prevalence of alterations in homologous recombination-related (HRR) genes and their association with platinum sensitivity. Methods: next-generation sequencing and promoter methylation of BRCA1 and RAD51C were performed on tumors from patients with mTNBC, using a panel of 19 HRR genes. Tumors were separated into three groups based on their molecular status: mutations in BRCA1/2, mutations in other HRR genes (BRCA1/2 excluded) or BRCA1/RAD51C promoter methylation and the absence of molecular alterations in HRR genes (groups A, B and C, respectively). Sensitivity to platinum-based chemotherapy was evaluated through the radiological response. Results: mutations in BRCA1/2 were detected in seven (13.5%) patients, while alterations in other HRR genes or hypermethylation in BRCA1 or RAD51C were reported in 16 (30.7%) patients; furthermore, no alteration was found in the majority of patients (n = 29; 55.8%). Among 27 patients who received platinum-based chemotherapy, the disease control rate was 80%, 55% and 18% (groups A, B and C, respectively; p = 0.049). Regarding group B, patients with disease control exhibited mutations in FANCL, FANCA and the RAD51D genes or RAD51C methylation; Conclusion: mutations in HRR genes and epimutations in RAD51C were associated with disease control through platinum-based chemotherapy. As such, apart from well-characterized alterations in BRCA1/2, a more comprehensive evaluation of HRD should be considered in order to enlarge the selection of patients with mTNBC that could benefit from platinum-based chemotherapy.