Osteosarcomas in BALB/c female mice.

Osteosarcomas were found in 16 of 24,192 (0.066%) BALB/c female mice, 14 were in 21,816 (0.064%) 2-acetylaminofluorene-treated mice, and two were in 2,376 (0.084%) untreated controls. The osteosarcomas were classified into osteoblastic, fibroblastic, and mixed types. Seven of the osteosarcomas metastasized to the lungs. The osteosarcomas in control and 2-acetylaminofluorene-treated mice showed little or no difference in the incidence, type, size, or site of origin, indicating that 2-acetylaminofluorene did not affect the development of osteosarcomas in BALB/c female mice.U