JAK2 and cancer: Eight out of these 52 genes are known to be involved in cancer: TP53, PIK3CA, JAK2, ATRX, MAP2K4, ERBB2, KMT2C and KMT2D. TP53 mutations were present in 28 (44%) tumours, including 21 missense mutations, 4 truncating mutations and 2 mutations altering splice junctions.