To investigate how overexpressing A3B affects tumor formation and progression, we crossed A3B‐Cre mice with p53+/− mice to generate four genotypes of A3B+ p53+/−, A3B+ p53+/+, A3B− p53+/−, and A3B− p53+/+, and observed their tumor formation and their survival. The gene discussed is TP53; the disease is neoplasm.