Incidence and type of tumors induced by DMBA carcinogenesis in H-2 congenic strains on a B10 background.

Five congenic strains on B10 background (B10, B10.S, B10.G, B10.BR and B10.A) were investigated for their susceptibility to tumor induction by 9,10 dimethyl-1,2 benzanthracene (DMBA). The DMBA was administered via a stomach tube five times at weekly intervals (total 5 mg). Two types of malignancies predominated: diffuse lymphocytic lymphomas with or without thymic involvement, and epidermal tumors. B10 (H-2b) was the most resistant strain when total tumor incidences were compared. B10.S (H-2s) had the highest incidence of both lymphomas and epithelial tumors and B10.G was significantly more susceptible to thymic lymphomas than B10. In B10.S mice thymic lymphomas were more frequent in males than in females, the reverse being true for tumors of epithelial origin. No correlation between tumor incidence and in vitro NK activity was demonstrated.