About a quarter of CAGI experiments have involved genes implicated in cancer (Fig. 1) and have included variants in BRCA1, BRAC2, PTEN, TPMT, NSMCE2 (coding for SUMO-ligase), CHEK2, the MRN complex (RAD50, MRE11, and NBS1), FXN, NPM-ALK, CDKN2A, and TP53. This evidence concerns the gene TPMT and cancer.