Mast cell neoplasia in mice.

Gross and histopathologic findings were reported for mast cell neoplasia in 2 female BALB/cStCrIBR mice. Microscopic findings included neoplastic mast cells in the liver, spleen, kidney and lymph nodes. Neoplastic mast cells were present in the blood smear of one of the animals.

Dose-response hyperplasia and neoplasia from feeding N-2-fluorenylacetamide (2-FAA) to BALB/c mice for varying time intervals.

Hyperplasia induced by N-2-fluorenylacetamide requires the continuous presence of the chemical for its maintenance. Feeding the chemical at levels of 8 to 86 ppm results in a dose-response related urinary bladder hyperplasia and, after 9 to 12 months, in bladder neoplasia at the higher dose levels. Neoplasia of the lungs, liver, parotid gland, lacrimal gland, harderian gland, and submaxillary gland was also observed. Measurement of oncogenic viruses revealed no synergism with 2-FAA and no relationship between virus counts and neoplasia. Calcareous pericarditis was observed and most general toxicological effects occurred in the liver. A pronounced sex difference in response was observed with the males giving greater responses than the females in all instances.