Many of these effects seem to involve the transcription factor and master regulator of metabolism hypoxia-inducible factor 1 (HIF1) (11, 12, 18), the overexpression of which has been demonstrated in BRCA1-related invasive breast cancer as well as ductal carcinoma in situ (DCIS), suggesting hypoxia to already play a role in early stages of BRCA1-related breast carcinogenesis (19, 20). This evidence concerns the gene BRCA1 and ductal breast carcinoma in situ.