As presented recently by Campone [84], CompLEEment-1 (NCT02941926) is a single-arm, open-label, multicenter phase IIIb study evaluating the safety and efficacy of ribociclib plus letrozole (RIB + LET) in a large, diverse cohort of patients who have not previously received endocrine therapy (ET) for advanced disease, in an intent to provide treatment alternatives for advanced male breast cancer HR+, HER2−. This evidence concerns the gene ERBB2 and male breast carcinoma.