CMTM5 and neoplasm: CMTM5, also called CKLF‐like MARVEL transmembrane domain containing member 5, is a member of CMTM family that could inhibit tumour growth.11 Being broadly expressed in human tissues, CMTM5 is usually down‐regulated in carcinoma tissues.12, 13 Restoration of CMTM5 may contribute to better morphological transformation, but the antitumour mechanism remains unclear.14 It was proposed that the understanding of the antitumour mechanism of CMTM5 was critical before it became a new target in the gene therapies for tumours.