The cytokine transforming growth factor-β1 (TGF-β1) is a crucial factor in tumor progression and a strong enhancer of EMT during tumor invasion and metastasis (Massagué, 2000; Siegel and Massagué, 2003; Derynck and Akhurst, 2007), therefore, next, to determine whether TGF-β1 is implicated in augmenting tumor cell proliferation, migration, and the factors that stimulate cancer, we studied TGF-β1 protein expression in HCT116 and RKO cells. The gene discussed is TGFB1; the disease is neoplasm.