Elevated expression of the human ras oncogene family in premalignant and malignant tumours of the colorectum.

Study of expression of ras-related oncogenes in human premalignant polyps and malignant tumours of the colorectum, as well as in normal colorectal mucosa, shows a significant elevation in the premalignant and malignant tissues as compared to their respective colorectal mucosa. These results suggest that activation of the ras oncogene family occurs in the development of colorectal tumours and that elevated expression at a premalignant stage may well be critical in the process of carcinogenesis but not in itself sufficient.