Several genetic polymorphisms exist in the TGF-β1 gene, one of which is a T → C transition at nucleotide 29 of the coding region, resulting in a leucine to proline substitution at codon 10 (Blobe et al, 2000; Breast Cancer Association Consortium, 2006; Cox et al, 2007). Here, TGFB1 is linked to breast cancer.