In contrast to the above genes with mutations that seemingly have low relevance to human cancers, alterations in Tp53, Cdkn2a, Erbb2, Chek2, Kras and Pik3r1 with homology to COSMIC variants were relatively common in rat gliomas and cardiac schwannomas (e.g. > = 50%). This evidence concerns the gene PIK3R1 and glioma.