CKLF like MARVEL transmembrane domain-containing 6 (i.e. CMTM6), previously termed chemokine-like factor superfamily 6 (i.e. CKLFSF6), is a transmembrane protein encoded in humans by the CMTM6 gene (also termed the CKLFSF6, PRO2219, ayoube, or gourari gene). This gene is located in band 22.3 on the short (or "p") arm of chromosome 3. CMTM6 protein belongs to the CKLF-like MARVEL transmembrane domain-containing family of proteins. This family consist of 9 member proteins: CKLF and CMTM1 through CMTM8. The CMTM family proteins are involved in autoimmune diseases, cardiovascular diseases, the male reproductive system, haematopoiesis, and cancer development. CMTM6 protein regulates immune responses to normal and abnormal (particularly cancerous) cells.