Chemically induced sarcomas in Sprague-Dawley rats: dose effects on autoantibody levels and tumor progression

We previously reported that a single injection of 2 mg benzo[a]pyrene (B[a]P) induced seric anti-phosphatidylinositol (PtdIns) autoantibodies (autoAb) and highly malignant sarcomas with 100% efficiency in Sprague-Dawley (SD) female rats. To evaluate the effects of lower doses, we administered a single dose (from 0.125 to 1 mg) of B[a]P into such rats. In all cases, we noted significantly high levels of anti-PtdIns autoAb, with clinically palpable tumors appearing around Day 100. Tumors grew more slowly than they did in the previous model (2 mg B[a]P). Both anti-PtdIns autoAb levels and first appearance of the tumor seemed to be independent of carcinogen doses. Conversely, tumor evolution seemed to depend on B[a]P doses.