HIGH-FREQUENCY OF K-RAS MUTATIONS IN HUMAN COLORECTAL HYPERPLASTIC POLYPS

Background-Hyperplastic polyps are common benign colorectal polyps, an d are thought to have Little association with malignant tumours in the colorectum. However, several reports suggest that some hyperplastic p olyps may develop into colorectal neoplasms. Aim-1 clarify genetic alt erations in colorectal hyperplastic polyps. Methods-Twenty eight color ectal polyps having serrated components were resected from patients en doscopically. The K-ras gene mutations in codons 12 and 13 were analys ed by PCR-RFLP. Intranuclear p53 protein was immunostained by the avid in-biotin complex method. Results-A mutation of the K-ras gene was det ected in nine (47%) of 19 hyperplastic polyps, and five (56%) of nine adenonnas. p53 protein nuclear accumulation was detected immunohistoch emically in two (22%) of nine adenomas, but not in any of the 19 hyper plastic polyps. Conclusion-Some hyperplastic polyps may be true neopla stic lesions, and could be precursors of malignant neoplasia.