Ductal carcinoma in situ (DCIS) shows overlapping epidemiology with invasive ductal carcinoma of the breast, sharing similar risk factorssuch as age, mammographic density, family history, and hormonal therapy as well as genetic factors such as BRCA1/BRCA2, histotypes, and molecular subtypes such as luminal A and B, HER2 enriched, and basal-type, thus suggesting its potential precursor role. This evidence concerns the gene BRCA1 and ductal breast carcinoma in situ.