Schwartz CJ, Pareja F, da Silva EM, et al. - The present study was conducted to explore the genotypic and phenotypic characteristics of breast cancers harboring somatic genetic alterations affecting genes of the SWI/SNF-related matrix-associated actin-dependent regulator of chromatin (SMARCs) family. A series of 6,026 primary and metastatic breast cancers subjected to targeted-capture sequencing was examined. Researchers distinguished SMARC core subunit (SMARCA4, SMARCB1, and SMARCA2) alterations in < 1% of all breast cancers, consisting of 27 primary and 30 recurrent/metastatic tumors. The results of this research indicate that SMARC alterations likely contribute to the biology of a rare subset of breast cancers in the form of biallelic or pathogenic alterations in SMARC, as evidenced by SMARC-deficient phenotype or altered expression of SMARC protein.