Similarly, although treatment of human breast cancer cells MCF-7 and ZR-75-1 with 5-aza-2′-deoxycytidine was shown to diminish cell proliferation and induce tumour suppressor genes, pro-metastatic genes such as plasminogen activator, urokinase (PLAU), which encodes urokinase (uPA), and transforming growth factor-beta 1 (TGFβ1) were induced via methylation of their promoters (Ateeq et al., 2008). This evidence concerns the gene TGFB1 and breast cancer.