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 oncoproteins or the malfunction of tumour-suppressor proteins. We examined the occurrence of the tumour proteins c-erb-B2 and c-fos and the tumour-suppressor protein p53 in 17 human embryos and fetuses with the help of immunohistochemistry. C-erb-B2 was detected mainly in embryonic tissue that are not known for c-erb-B2-overexpression in tumours in the adult. In contrast, c-fos was almost always located in fetal tissues corresponding to its location in adult tumours. Staining for p53 was found in a wide variety of embryonic and fetal tissues. C-erb-B2 and p53 were localized in the same tissue structures of the developing skin, heart and muscle. In other tissues, e.g. muscle and bone, c-fos was found together with p53, suggesting an antagonistic action of these proliferative and antiproliferative factors. Furthermore, c-erb-B2. c-fos and 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 development of these tissues.
Embryo, Mammalian Embryonic and Fetal Development