Proto-oncogene activation in surgical specimens of rectal carcinoma.

26 rectal carcinoma samples were screened for proto-oncogene activation. In addition, seven normal mucosae taken at a distance of 10 cm from the tumor were analyzed. Our results are based on hybridization assays of 32P labelled cDNA synthesized on cellular poly (A+)RNA with proto-oncogene dot-blots. This analytical concept offers the advantage of a comprehensive analysis of very limited amounts of biopsy material. Multiple proto-oncogenes could be detected as being over expressed for the analyzed rectal carcinomas. However, morphologically inconspicuous mucosae from tumor patients, classified as such by the pathologist, also already show clear signals of proto-oncogene over expression.