THE ONCOPROTEINS C-ERB-B2, C-FOS AND THE TUMOR-SUPPRESSOR PROTEIN P53IN HUMAN EMBRYOS AND FETUSES

Oncoproteins and tumour-suppressor proteins are thought to possess an antagonistic function in the regulation of growth and differentiation processes during embryonic and fetal development. In contrast, in the adult, tumour growth is associated with the overexpression of oncoprot eins or the malfunction of tumour-suppressor proteins. We examined the occurrence of the tumour proteins c-erb-B2 and c-fos and the tumour-s uppressor protein p53 in 17 human embryos and fetuses with the help of immunohistochemistry. C-erb-B2 was detected mainly in embryonic tissu e that are not known for c-erb-B3-overexpression in rumours in the adu lt. In contrast, c-fos was almost always located in fetal tissues corr esponding: to its location in adult tumours. Staining for p53 was foun d in a wide variety of embryonic and fetal tissues. C-erb-B2 and p53 w ere localized in tile same tissue structures of the developing skin, h eart and muscle. In other tissues, e.g. muscle and bone, c-fos was fou nd together with p53, suggesting an antagonistic action of these proli ferative and antiproliferative factors. Furthermore, c-erb-B2, c-fos a nd p53 appear to be important for growth and differentiation processes in human development as the occurrence of these proteins was not only restricted to specific tissues but also to specific stages of develop ment of these tissues.