[Expression of immunohistochemical differentiation markers in normal and transformed neoplastic neuroectodermal stem...

The cells of primitive neuroectodermal tumours may undergo differentiation and, eventually, may be transformed to neurons, glial cells, and ependymal cells. Early stages of neuroectodermal differentiation may primarily be determined by means of immunohistochemical methods. Immunohistochemical investigations were performed on brains of human foetuses obtained from the 18th to 36th weeks of pregnancy, with a view to elucidating the process of maturation during foetal development and to determining the antigens identifiable in cells in the course of differentiation, following fixation in formalin and embedding in paraffin. Gliafibrillar acid protein (GFAP) and vimentin proved to be of particularly high stability and, consequently, were easily detectable from paraffin material. The same antigens were focally recordable also from eight of 17 primitive neuroectodermal tumours. Clues were rare in these tumours as to neuronal differentiation. This was attributed to instability of neurofilament proteins under conditions of formalin fixation and paraffin embedding.