Autotransplantation of colonic tumors into the colonic wall of the rat.

Colonic tumors were induced in Sprague-Dawley rats by weekly subcutaneous injections of 1,2 Dimethylhydrazine (DMH) for 4 months. The animals were thereafter laparotomized and a palpable tumor was transplanted into the same animal in a tumor-free area of the transverse colon. Autotransplanted tumors were considered those tumors growing in the wall of the transverse colon, covered by intact colonic mucosa. The frequency of autotransplanted tumors was 34%. The possibility that autotransplantation may also occur in humans by accident, during procedures to remove a colorectal adenocarcinoma, is discussed.