DNMT3A and cancer: Examples of such positive controls include DNA methyltransferase (DNMT3A or DNMT3B) enzymes37 that were consistently among the top variables in all cancers (Fig. 4f,g and Supplementary Fig. 11a–f), and patient's age (or age at diagnosis)12, 38 that was highly ranked in prostate, colon, breast, kidney and brain (Fig. 4f,g and Supplementary Fig. 11a–f).