Phenotypic and genetic alterations in pre-cancerous cells in the colon.

Cell dysplasia in polyps and in ulcerative colitis are thought to be the pre-cancerous lesion leading to invasive colon cancer. Many polyps and dysplastic lesions in ulcerative colitis have phenotypic changes (blood group antigen, cytokeratins, CEA, TAG-72.3 antigen expression) and genetic changes (c-K-ras mutation, enhanced c-myc expression and pp60c-src activity) which are characteristic of invasive cancers. Thus, these early pre-cancerous lesions may be a late stage in the genetic evolution of colon cancer.