We observed that (i) the average tumor incidence in bitransgenic mice infected with RCASBP-Bcl-xL (n = 10) was 2-fold higher than that in bitransgenic mice injected with the control RCASBP-ALPP viruses (n = 6); (ii) mice infected with RCASBP-Bcl-xL (n = 10) exhibited a higher incidence of invasive carcinomas than did mice that received the control viruses (n = 6); and (iii) mice infected with RCASBP-Bcl-xL displayed a higher tumor burden than controls (p = 0.003, n = 6 for each group, Wilcoxon rank sum test). The gene discussed is BCL2L1; the disease is neoplasm.