Occurrence of Mammary Tumors, Reticular Neoplasms, and Pulmonary Tumors in Strain BALB/cAnDe Breeding Female Mice

Summary

The occurrence of mammary tumors, reticular neoplasms, and pulmonary tumors in breeding female mice of the BALB/cAnDe subline was recorded. Of 152 breeding females autopsied at an average age of 17 months, 33 or 22 percent developed mammary tumors and 119 or 78 percent were free of mammary tumors. The mice with mammary tumors produced an average of 7.6 litters, while those without mammary tumors produced an average of 7.3 litters. The most frequently occurring type of mammary tumor was the adenoacanthoma. Of 182 breeding females, 18 or 10 percent had developed reticular neoplasms at an average age of 19 months and 164 or 90 percent were free of reticular neoplasms at an average age of 15 months. The most frequently occurring type was the reticulum cell neoplasm, type B. Of 169 breeding females, 44 or 26 percent had developed pulmonary tumors at an average age of 17 months and 125 or 74 percent were free of pulmonary tumors at an average age of 16 months. Because of the variation in tumor frequency in different sublines of mice and the extensive use of BALB/c as test animals, the information on the number of different types of tumors in untreated mice of the BALB/cAnDe subline should prove useful.