Figure 1.

Expression of PER 2 in human breast epithelial and breast cancer cell lines. Total cellular protein was isolated from two immortalized human breast epithelial cell lines (HME-tert and MCF-10A), two ERα-positive human breast tumor cell lines (MCF-7 and T47D lines) and one ERα-negative human breast tumor cell lines (MDA-MB-231 line). One hundred micrograms of total cellular protein from each cell line was separated by 10% polyacrylamide gel electrophoresis and subjected to Western blot analysis using an antibody directed against the human PER 2 protein.