In particular, EWS regulates AS of genes playing a key role in oncogenesis [51] like CHEK2 (described above), BRCA1 (breast cancer 1 gene), and ABL1. BRCA1 is a tumor suppressor and germline mutations in BRCA1 gene predispose individuals to breast and ovarian cancers [97]. This evidence concerns the gene BRCA1 and breast carcinoma.