[Detection of factors of differentiation in human malignant melanoma]

Factors of differentiation (FD) have been detected and isolated from human melanomas cloned in nude mice as well as from amphibian embryos from neurula--early tail bud stage. It has been shown that each source contains two factors of differentiation--mesodermalizing (MF) and melanogenic (MgF). Biological activity of MF has been determined by its capacity to initiate in early embryonic multipotent cells the appearance of various cell types, normally arising from mesoderm. Biological activity of MgF have been determined by its capacity to initiate melanogenesis both in epithelial cells and in dermal melanophores of clawed toad. It has been shown that both factors, isolated from both sources are heterogeneous by their molecular weights. Mr values determined for MgF, isolated from both sources, are nearly identical whereas Mr values of MF from sources coincide partially. Resemblance of FD detected in remote representatives of animal kingdom suggest the high evolutionary conservatism of factors, which switch on cell differentiation.