Cellular and Molecular Events Involved in Tumour Progression in Colorectal Carcinogenesis: A Study of the Adenoma Carcinoma Sequence In Vitro

Epithelial cell lines from hereditary and sporadic adenomas have been isolated with abnormalities of chromosomes 1, 7, 14, 17, 18 and 22. Chromosome 1 may be involved in in vitro immortalization. Several stages have been described in the transformation of an adenoma cell line to anchorage independence and a possible role for sodium butyrate in tumour promotion discussed. In vitro immortality, aneuploidy, clonogenicity, resistance to sodium butyrate, ras gene activation and production of active proteinases are potential markers of tumour progression. A role for a constitutively produced tumour promoter(s) in colorectal carcinogenesis is discussed together with a possible different mechanism for adenoma formation in sporadic versus hereditary cancer patients.