Genes mutated in AML fall into several functional categories: transcription factors (e.g., oncofusions, mutated AML1), signalling genes (e.g., FLT3-ITD, mutated c-KIT), DNA-methylation-associated genes (e.g., DNA methyltransferase 3A gene (DMNT3A), IDH1/2, TET2), chromatin-modifying genes (e.g., MLL-oncofusions), molecular chaperones (NPM1), tumour suppressor genes (e.g., TP53), and spliceosome- and cohesion-complex genes [4]. The gene discussed is TET2; the disease is acute myeloid leukemia.