TGFB1 and breast cancer: Although mutations in genes encoding proteins in the TGF-β signalling pathway are uncommon in human breast cancers, loss or diminished expression of TGF-βRII confers a 3.4-fold greater risk of developing invasive breast carcinoma in a subset of patients [3] and is associated with higher histological grade in human breast in situ and invasive carcinomas [4].