CYTOKINE-PRODUCING MAMMARY CARCINOMAS IN TRANSGENIC RATS CARRYING THEPX GENE OF HUMAN T-LYMPHOTROPIC VIRUS TYPE-I

In two lines of transgenic rats (pX rats) from WKAH and F344 strains a nd carrying the human T-lymphotropic virus type I pX gene, undifferent iated mammary carcinomas developed predominantly in females starting a t about 5 months of age, and there was massive infiltration of granulo cytes in the tumor tissue. The incidence of the tumor reached about 40 % when the rats were 12 months old. mRNAs of both pX and host genes Gr o and MIP-2, which are granulocyte chemoattractants of the interleukin 8 family, were highly expressed in the tumor tissue. Since expression and point mutation of several oncogenes and the antioncogene were not demonstrated, hitherto unidentified novel oncogenic pathways may be t ransactivated by the pX transgene in these pX rats.