Canine mammary carcinomas and their metastases have significantly decreased expression levels of TGF-β and latent TGF-β binding protein 4 (LTBP4) than non-neoplastic mammary glands and canine mammary adenomas [23], suggesting that loss of their expression may have growth-stimulatory effects in advanced tumours. This evidence concerns the gene TGFB1 and breast carcinoma.