CD4 and colorectal carcinoma: To probe for arelationship between the ADK expression level and the numberof T cells involved in adenosine generation, the relative contents ofCD39+/CD73+ effector T cells (CD4+ T helpers and CD8+cytotoxic cells) and suppressive Treg cells were analyzed in CRC patients(n = 20) and healthy donors (n = 17)(Fig. 2).