A BRCA1 or BRCA2 mutation was identified in 15 of 564 Polish cases of DCIS (2.7%), including BRCA2 mutations (four variants: c.658_659del, c.3847_3848del, c.5946del and c.7913_7917del) seen in eight (1.42%) cases and BRCA1 mutations (two variants: c.5266dup, c.4035del) observed in seven (1.24%) cases. This evidence concerns the gene BRCA1 and ductal breast carcinoma in situ.