Tumor Induction in Praomys (Mastomys) natalensis by N,N′-2,7-Fluorenylenebisacetamide

Feeding N,N′-2,7-fluorenylenebisacetamide (CAS: 304-28-9) at 0.025% to 15 male and 15 female mastomys considerably shortened their life-span. At death every treated mastomys had several primary tumors; untreated animals at comparable ages had none. Several mastomys with hepatoblastomas and 1 with giant cell hepatitis and a metastasizing pancreatic carcinoma are first reported here. The tumor load per animal averaged 4.0 for treated females, 2.6 for treated males, 1.5 for untreated females, and 0.6 for untreated males. Of 24 hepatic tumors in treated mastomys, 11 metastasized, compared to none of the incipient tumors in 8 of 26 untreated animals. Pancreatic adenomas developed in 27 treated and 1 untreated mastomys, and a metastasizing adenocarcinoma developed in 1 treated animal. All treated females, 3 treated males, and 1 untreated female developed multiple villous adenomas in the small intestine. One untreated female and 8 treated females developed mammary cancers, 4 of which metastasized. Primary tumors of other sites occurred infrequently.