title: Induction of rectal carcinoma in mice by local x-irradiation.
abstract: The pelvic region of random bred female ICR-JCL mice and CF1 mice was irradiated with various doses of X-rays at 1-week intervals to determine the relationship between the X-ray dose and induction of rectal carcinoma. The incidence of rectal carcinoma in ICR mice was zero after a single dose of 2,000 rad of X-rays, but 31% after a single dose of 3,000 rad, 6% after 2 doses of 1,500 rad, 25% after 3 doses of 1,500 rad, 42% after 2 doses of 2,000 rad, and 95% after 3 doses of 2,000 rad. This cancer developed in 70% of CF1 mice exposed to 2 doses of 2,000 rad. No case of this tumor was observed in the control animals not exposed to X-rays. The development of this tumor was found to depend on the X-ray exposure dose. Local X-irradiation of the pelvic region is one of the effective methods for inducing rectal carcinoma in mice. Rectal cancers induced by X-irradiation were adenocarcinoma of the tubular, papillary, and mucinous type, and frequently showed invasive growth into the deep layers of the rectal wall.
mesh_terms: D000230:Adenocarcinoma / Q000209:etiology / Q000473:pathology; D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000209:etiology / Q000473:pathology; D004307:Dose-Response Relationship, Radiation; D005260:Female; D007413:Intestinal Mucosa / Q000528:radiation effects; D051379:Mice; D009374:Neoplasms, Experimental / Q000209:etiology; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D012004:Rectal Neoplasms / Q000209:etiology* / Q000473:pathology; D012007:Rectum / Q000528:radiation effects; D013274:Stomach Neoplasms / Q000209:etiology; D013997:Time Factors; D014965:X-Rays