As it has been described that several tumor entities are positive for Foxp3, CTLA-4 or CD39/CD73 [6, 16–18], all of them Treg associated markers, we reasoned whether also GARP, a recently described Treg activation marker involved in tolerance induction[9], is expressed on melanoma cells and would functionally contribute to the inhibitory features mentioned above. This evidence concerns the gene ENTPD1 and neoplasm.