TP53 and neoplasm: As in homozygotes, also in p53 heterozygous mice the general tumor load was similar in BALB-p53+/− and RGKO-p53+/−(median 2, range 1–6, and median 2, range 1–10, respectively) but the proportion of mice with multiple tumor histotypes was significantly increased in RGKO-p53+/− mice (Fig. 5).