EpCAM protein expression. (A) Western blot analysis of EpCAM in the stable transfectants and control cell lines. Observation of the appearance of two protein species (43 and 34 kDa). Actin was used as loading control. Its molecular weight is about 45 kDa. (B) PNGase F treatment of MCF-7 cells. To analyse if the two EpCAM protein species derive from distinct glycosilations, MCF-7 lysates were incubated with the glycosidase PNGase F. As both protein bands shift in height, N-linked glycosilation is not responsible for the existence of two species (* = potential degradation products).