Histology, histochemistry, tumor and serum markers in gastrointestinal tract cancer

Integration of morphologic and molecular information is being pursued as a result of more extensive use of in situ hybridization techniques. Oncogenes, gene products, and viral genomes involved in the genesis and progression of gastrointestinal tumors have been located in specific histotypes or tumor sectors. The main advances in this area relate to cell-matrix interactions and the biologic mechanisms of tumor invasion. Some aspects of the morphogenetic sequences of gastric and colorectal adenocarcinomas and hepatocellular carcinoma have been elucidated. Studies of DNA ploidy have furnished results consonant with carcinogenesis models envisaging sequential genome alterations due to genetic instability of the transformed cell. The prognostic role of DNA content in gastrointestinal tumors, however, has not been unequivocally established. Research on tumor markers has been directed toward the tissue expression and distribution of apomucins with different molecular structures. Evaluation of tumor markers in body fluids has proved inadequate for the early detection and screening of gastrointestinal neoplasia. Some interesting results have been reported with regard to the monitoring of gastric and colorectal carcinomas by means of serum tumor markers.