Spontaneous Neoplasms in Germfree BALB/cPi Mice

SummaryOf 67 germfree BALB/cPi mice autopsied at a median age of 21 months, 14/67 (21%) had lung tumors; 5/67 (8%), reticular neoplasms; and 4/67 (6%), angiomas. Mammary tumors, squamous cell carcinomas, adrenal cortical carcinomas, hepatomas, an ovary carcinoma, and a myoepithelioma were also observed. There was no discernible difference between the incidence of tumors observed in germfree BALB/cPi mice and that reported in the literature for conventional BALB/c mice.