The BRCA BCY Collaboration (ClinicalTrials.gov identifier: NCT03673306) is the largest global cohort of BRCA carriers with diagnosis of breast cancer at young age.11 Hence, this study represents a unique real-world cohort to explore the clinical behavior of breast cancer in young BRCA1 and BRCA2 carriers separately and the association of the timing of genetic testing with prognosis. This evidence concerns the gene BRCA1 and breast cancer.