Epcam

Transmembrane protein that is of crucial importance as a marker of embryonic stem cells for embryogenesis and carcinogenesis. It is also jointly responsible for cell proliferation.

Stem and progenitor cells carry this protein in their membrane in high molecule numbers. As soon as the stem cells become differentiated tissue cells, the cells largely stop expressing EpCAM. For a long time, EpCAM was regarded as a cell-cell adhesion molecule. However, it appears to play an essential role in the activation and regulation of stem cell genes. Furthermore, it is able to activate the oncogene c-myc, which induces cell proliferation, including the proliferation of tumor cells. EpCAM is currently regarded as a stem cell marker of carcinomas and is overexpressed on many carcinomas. The basal cell carcinoma expresses this marker to a high degree, in contrast to the spinocellular carcinomas of the skin. This supports the hypothesis that basal cell carcinoma originates from epidermal stem cells located in the hair follicle bulge or undifferentiated cells of the outer root sheath.