STK11 and neoplasm: Liver kinase B1 (LKB1) loss augments DNA methylation through activation of de novo serine biosynthesis.114 Serine hydroxymethyltransferase 2 (SHMT2), a key enzyme of serine biosynthesis in mitochondria, has been observed to promote histone and DNA methylation by increasing SAM synthesis.115 In addition, an enhancement of αKG levels has been found to lead to the differentiation of tumour cells in a 5-hydroxymethylcytosine (5hmC)-dependent manner.116 Methyl donor SAM replenishment is derived from dietetic methionine, serine, vitamins B2, B6 and B12, and folate.