Tumor onset is accelerated in p53^+/− mice lacking CD1d-restricted NKT cells. (A) Groups of p53^+/− (C57BL/6 WT, CD1d^−/−, and Jα18^−/−) mice were aged, and the incidence of tumors (verified by histology as the proportion of the whole starting cohort with tumor) was determined after 750 days. (*P < .05; **P < .01; ns, not significant, using a Fisher exact test compared with B6 p53^+/− control mice.) Survival curves depict the survival of p53^+/− BL/6, p53^+/−CD1d^−/−, and p53^+/−Jα18^−/− mice (excluding the small number of those dying of unknown causes) monitored for 750 days (B). Panels (C: female) and (D: male) show survival curves of the same mice, divided on the basis of sex. Data are presented as percentage of survival over time. (*P < .05; ***P < .001, using a log-rank test compared with B6 p53^+/− control mice.) The age at death of tumor burdened total (E), female (F), and male (G) mice is represented in scatterplots showing mean plus or minus SEM. Cohort sample sizes: n = 139 B6 p53^+/− mice (n = 60 female and n = 79 male), n = 39 p53^+/−Jα18^−/− mice (n = 22 female and n = 17 male), n = 61 p53^+/−CD1d^−/− mice (n = 36 female and n = 25 male). (*P < .05; ***P < .001 using a Kruskal-Wallis test compared with B6 p53^+/− control mice.)