[Analysis of oncogene and its expression at cellular level].

Remarkable progresses have been made in the field of oncogenes in the last several years. More than 40 oncogenes or proto-oncogenes were identified by transfection assay and by weak homology of base sequences with known oncogenes. Many of them were shown to play a specific role in regulation of cell growth and signal transduction, but their exact roles in development and progression of human cancers are still not clear. Study of oncogenes and their expression at cellular level using immunohistochemistry and in situ hybridization will contribute to understand how oncogenes are involved in the multiple steps of carcinogenesis. In this article, application of newly established monoclonal antibodies to ras p21 for immunohistochemistry and immunoblotting analysis and possibilities of DNA analysis using formalin-fixed paraffin-embedded blocks are discussed.