home edit2 whole TSD November 2002 PDF format - OEHHA

Table 2.
2,4-Diaminotoluene-induced tumor incidence in F344 rats and B6C3F 1 mice
(NCI, 1978)
Sex/species Study group Average dose a
(mg/kg-day)
Tumor type
Tumor
incidence b
Male rats matched controls 0 liver tumors c 0/20
subcutaneous fibromas 0/20
low dose 3.2 liver tumors c 5/50
subcutaneous fibromas 15/50
high dose 7.0 liver tumors c 10/50
subcutaneous fibromas 19/50
Female rats matched controls 0 liver tumors c 0/20
mammary gland tumors 0/20
low dose 3.95 liver tumors c 0/50
mammary gland tumors 11/50
high dose 8.55 liver tumors c 6/50
mammary gland tumors 14/50
Female mice matched controls 0 liver tumors 0/20
lymphomas 2/20
low dose 13.0 liver tumors 13/50
lymphomas 29/50
high dose 26.0 liver tumors 18/50
lymphomas 11/50
a. Doses as reported by Gold et al. (1984).
b. Tumor incidences as reported by Gold et al. (1984)
c. Includes hepatocellular neoplastic nodules, adenomas and carcinomas
IV.
DERIVATION OF CANCER POTENCY
Basis for Cancer Potency
Results of the NCI (1978) feeding studies of 2, 4-diaminotoluene in male and female B6C3F 1 mice and
F344 rats are listed by Gold et al. (1984). Significant increases in tumors were seen in rats of both
sexes and in female mice. The study results indicated that rats are more sensitive than mice. The female
rat appears to be slightly more sensitive than the male, although the study is not sensitive enough to
definitively distinguish between the two. Cancer potency is based on mammary gland tumors in the
female rat (see Table 2).
235