EGF and plasma cell myeloma: Although, it is reported that protein kinase C (PKC) activation by the phorbol 12-myristate 13-acetate (PMA) induces SDC-1 shedding in myeloma cells and that its inhibition reverts this effect, PKC signaling cascade is not involved in EGF- and thrombin-mediated shedding (37, 121).