NT5E and melanoma: Although ATP released from tumor cells may serve as a DAMP to promote DC activation (see Induction of Immunogenic Cell Death (ICD) as a Means of Promoting DC-Mediated Antitumor Immunity), melanoma cells often express on their surface the CD39 and CD73 ectonucleotidases that hydrolyze ATP into adenosine (170–172), thereby leading to its buildup in the tumor microenvironment.