The Genomic Landscape of Male Breast Cancers
A partir d'échantillons tumoraux prélevés sur 59 patients masculins atteints d'un cancer du sein, cette étude identifie un ensemble d'anomalies génomiques et les compare avec les anomalies observées en population féminine
Purpose: Male breast cancer (MaBC) is rare and its genomic landscape has yet to be fully characterized. Lacking studies in men, treatment of MaBC patients is extrapolated from results in females with the disease (FBC). We sought to define whether MaBCs harbor somatic genetic alterations in genes frequently altered in FBCs. Experimental Design: All MaBCs were estrogen receptor-positive and all but two were HER2 negative. 59 MaBCs were subtyped by immunohistochemistry and tumor-normal pairs were microdissected and subjected to massively parallel sequencing targeting all exons of 241 genes frequently mutated in FBCs or DNA-repair related. The repertoires of somatic mutations and copy number alterations of MaBCs were compared to that of subtype-matched FBCs. Results: 29% and 71% of MaBCs were immunohistochemically classified as luminal A-like or luminal B-like, respectively. MaBCs displayed a heterogeneous repertoire of somatic genetic alterations that to some extent recapitulated that of estrogen receptor (ER)-positive/HER2-negative FBCs, including recurrent mutations affecting PIK3CA (20%) and GATA3 (15%). ER-positive/HER2-negative MaBCs, however, less frequently harbored 16q losses, and PIK3CA and TP53 mutations than ER-positive/HER2-negative FBCs. In addition, MaBCs were found to be significantly enriched for mutations affecting DNA repair-related genes. Conclusion: MaBCs less frequently harbor somatic genetic alterations typical of ER-positive/HER2-negative FBCs, such as PIK3CA and TP53 mutations and losses of 16q, suggesting that at least a subset of MaBCs are driven by a distinct repertoire of somatic changes. Given the genomic differences, caution may be needed in the application of biological and therapeutic findings from studies of FBCs to MaBCs.