Tumor suppressor genes as negative growth regulators in development and differentiation.

Tumor suppressor genes have received much attention for their roles in the development of human malignancies. However, their gene products (proteins) function as negative growth regulators and are highly expressed in many tissues during embryonic development, suggesting that they might function as critical proteins in differentiation and development. The evidence implicating tumor suppressor proteins in cellular differentiation and embryonic development will be presented with special attention to the neurofibromatosis 1, neurofibromatosis 2, and tuberous sclerosis 2 gene products.