In addition, incubation of MDA-MB-231 and HCC1937 breast cancer cells with TGF-β1 (10 ng/mL, for 24 h) led to a 1.5–twofold increase in the level of CCL2 promoter activity in the luciferase reporter system (Fig. 2C). Here, TGFB1 is linked to breast carcinoma.