Recent studies showed that m6A modification played essential roles in tissue development, stem cell formation and differentiation,24, 25 control of heat shock response 26 and circadian clock controlling,27 as well as in tumours formation.28, 29, 30, 31, 32, 33, 34, 35 As the critical m6A methyltransferase, the role of METTL3 in tumours is controversial. The gene discussed is CLOCK; the disease is neoplasm.