TP53 and squamous cell carcinoma: Belinsky et al. [78] identified that exposure of F344 rats to the alpha emitter Pu-239 did not sufficiently suggest that the TP53 mutation underlies the aetiology of the genesis of rat lung tumors with just 7% (2/29) of rat squamous cell carcinomas representing alterations of the TP53 gene, both of which were G to A transitions at codons 280 and 283.