Latency and clonality analysis of SRS19-6–injected mice. (A) Kaplan-Meier survival curves of SRS19-6–injected mice of the following genotypes: Cebpa^+/+ (+/+; n = 22), Cebpa^+/BRM2 (+/BRM2; n = 21), and Cebpa^BRM2/BRM2 (BRM2/BRM2; n = 35). The Cebpa^BRM2/BRM2 animals have significantly shorter mean latency (P < .001; 2-tailed log-rank test) than the other genotypes. (B) Representative Southern blotting of splenic tumor DNA from SRS19-6–injected mice restricted with HindIII and probed with a probe against the SRS19-6 env open reading frame. Cebpa^BRM2/BRM2 animals generally have fewer integrations.