Retrieval and amplification of DNA from unstained histopathological sections

Testing of compounds for carcinogenic potential in vivo involves various experimental designs. A few of these techniques are directed to demonstrate the genotoxicity and mutagenicity of the compound by histopathology. These changes shown by histochemical means include monoclonal antibody directed cellular markers. Development of the polymerase chain reaction technique (PCR) for amplification of DNA has facilitated the investigation of molecular events related to the formation of malignant neoplasms. We describe here a method for screening tissues for mutations of the H-ras gene using monoclonal antibodies directed toward normal and mutant p21 proteins. Formalin-fixed, paraffin-embedded tissue sections are used to subsequently confirm the gene mutation by PCR amplification of the H-ras gene. The results indicated a successful application of this technique to demonstrate the presence of p21 oncoprotein in the tissues tested.