ATM and cancer: The number of RET ATA mutations observed in the COSMIC genetic and genomic dataset increased substantially according to the mutation's aggressiveness: 94.1% of the ATA RET mutations occurring in cancers belong to the ATA C–D classification (strong mutations), while only 1.4% are weak ATA-A RET mutations (Fig. 3 and Supplementary Tables 2 and 3, see section on supplementary data given at the end of this article).