In a research involving patients with melanoma, soluble PD-L1 (sPD-L1) levels were found to be higher in patients with severe OSAHS than in those with mild OSAHS or non-OSAHS patients [82], indicating that the sPD-L1 concentration might be related to the degree of oxygen deficiency. This evidence concerns the gene CD274 and obstructive sleep apnea syndrome.