MDM2 and lymphoma: The differences in the number of sarcomas (8 in 19 mice versus 15 in 20 mice; p = 0.037, chi-squared test) and lymphomas (14 in 19 mice versus 8 in 20 mice; p = 0.034, chi-squared test) that developed in Mdm2+/−Arf−/−p53−/− mice compared to Mdm2+/+Arf−/−p53−/− mice were statistically significant.