responsible for the refractoriness of the mammary gland to carcinogenesis.PMID: 15987443 [PubMed - indexed for MEDLINE] PMCID: PMC1143568 Free PMC ArticleShareImages from this publication.See all images (2)Free textFigure 1An initial mutagenic event in the primitive ductal structures of the breast taking place early in life, such as before or during puberty, can multiply during the process of bra