Determination of cell markers by (A) Western blot and (B) immunofluorescence. ETCC001 and the hTERT transfected cell lines expressed various markers. MCF7 cells were used for comparison to our DCIS cell lines. In the Western blot, the pan cytokeratins antibody could detect multiple cytokeratins in MCF7 cells but our cell lines expressed only 1-2 of these cytokeratins. DAPI was used to stain nucleus in the immunofluorescence study. Images were captured with Zeiss LSM 5 Meta microscope at 100× magnification. Pan-CK: Pan-cytokeratin; CK19: cytokeratin 19; ER: estrogen receptor; PR: progesterone receptor; EMA: epithelial membrane antigen.