Figure 1: Immunofluorescence analyses of CK18 and ER antibodies in breast cancer spheres from MCF7 and MDA-MB-231 cancer cell lines. MCF7 (A) and MDA-MB-231 (B) breast cancer spheres were stained using CK18 antibody, a breast luminal epithelial cell marker. Strong staining of CK18 was detected in breast cancer spheres of untreated and treated with TGF beta during 24 and 48 hours. Whereas the positive staining of ER, a hormone-dependent breast cancer marker was only restricted in MCF7 cancer spheres (A) of untreated and treated with TGF beta during 24 and 48 hours. TGF beta stimulation did not change the expression of CK18 and ER in both MCF7 (A) and MDA-MB-231 (B) breast cancer spheres. CK18 was stained with Alexa 488 green labeled and ER was stained with Alexa 568 red labeled secondary antibodies. Original magnification: 400X.