Abstract
BACKGROUND: Skin cutaneous melanoma (SKCM) is one of the most lethal skin malignancies worldwide. Sphingosine 1-phosphate (S1P) regulates tumor cells through S1P receptors (S1PRs). Unlike S1PR1/2/3/5, whose anti-apoptotic effects have been widely studied, the regulatory effect of S1PR4 on tumors has not been studied extensively. In this study, we aimed to investigate the correlation between S1PR4 expression and survival, clinical manifestations, tumor microenvironment, and immune infiltration in patients with SKCM. RESULTS: Low S1PR4 expression was associated with poor prognosis in patients with SKCM. Patients in the high-expression group had significantly longer disease survival and progression-free survival than those in the low-expression group. CONCLUSION: High S1PR4 expression was highly associated with better prognosis and milder clinical manifestations; thus, S1PR4 may be used as a prognostic marker to help physicians monitor patients with SKCM.