Additional biomarkers from peripheral blood samples have been studied in melanoma, e.g., neutrophil-to-lymphocyte ratio (NLR)13,14, serum lactate dehydrogenase (LDH) levels15,16, cytokines and lymphocyte populations [interleukin (IL)-6, cluster of differentiation (CD)73, CD8+CD73+ T cells]17–19. Here, NT5E is linked to melanoma.