Risk and surveillance of individuals with heritable factors for colorectal cancer. WHO Collaborating Centre for the Prevention of Colorectal Cancer.

摘要: Heritable and genetic factors pertinent to colon cancer can be divided into three categories: inherited syndromes, epidemiology, molecular genetics. Familial adenomatous polyposis (FAP) Gardner syndrome (GS) are rare dominantly syndromes characterized by hundreds thousands of colonic polyps. Colon occurs at a young age in both diseases unless the is removed. Peutz-Jeghers familial juvenile hamartomatous conditions with less dramatic, but definite, increased risk for cancer. These four together account than 1% cases malignancy. Hereditary nonpolyposis colorectal form an early onset predilection proximal tumours. Multiple primary malignancies frequently observed one or several polyps often present affected individuals; 4-6% occur relationship this syndrome. Genetic epidemiological studies have consistently shown that first-degree relatives persons twofold threefold having More recent found similar among those Studies pedigrees further demonstrated clustering probably on basis partially penetrant susceptibilities. susceptibilities interact environmental give rise polyp growth finally Molecular begun elucidate mechanisms DNA level. The germinal mutation FAP GS has been localized long arm chromosome 5. Tissue samples from "random" cancers frequent specific acquired sequence deletions chromosomes 5, 17, 18. Mutations over-expression ras oncogene likewise such tissues. 5 defect tissues same locus as FAP. There evidence normally regulates expression c-myc oncogene, which turn regulatory function replication. 17 deletion gene transformation-associated protein, p53. Appropriate screening starting relatively necessary prevent syndromes. Screening also indicated close nonsyndromic common view moderately group.(ABSTRACT TRUNCATED AT 400 WORDS)