TP53 and squamous papilloma: Namely, the percentage of mice with the KrascomG12D/+ alleles that had the most severely graded oral lesions of squamous papilloma decreased from 100% to 75% with an extra copy of Trp53, while there was a clear shift from more severe lesions of marked and moderate ASH to less severe lesions of mild ASH or no lesions in the KrascomQ61R/+ background with increased p53 dosage (Fig 2A).