Effect of iron deficiency on DMH-induced gastrointestinal tract tumors and occurrence of hepatocyte abnormalities in Fischer rats.

The relationship between iron deficiency and carcinogenesis was studied using the carcinogen dimethylhydrazine to induce gastrointestinal tumors in Fischer 344 control and iron-deficient rats. Dimethylhydrazine (30 mg/body wt) was administered by gastric intubation 10 times over nine weeks. After 32 weeks, rats were sacrificed, and tumor incidence was assessed. The overall incidence of gastrointestinal tract tumors (colonic and duodenal) was higher in the iron-deficient (66%) than in the control group (46%). Whereas the incidence of colonic tumors was identical in control and iron-deficient groups, the duodenal tumor incidence was significantly elevated in iron deficiency. Five of 15 rats, i.e., 33.3%, in the iron-deficient group developed duodenal tumors; in the control group, only 1 of 15 rats developed a tumor (i.e., 6.6%). Also, iron-deficient rats had multiple tumors. Histological examination of the colon and duodenum revealed that the tumors were adenocarcinomatous in nature. Another notable feature in the iron-deficient group was the presence of atypical cells in the livers of carcinogen-treated iron-deficient rats. This study thus suggests that there is a greater incidence of tumors in iron deficiency and that the proximal part of the intestines seems to be the preferred site. The presence of atypical cells in the liver suggests that in iron deficiency, besides gastrointestinal tract tumors, the liver may also be a favored site for abnormalities.