Here, the frequency of 5′-ectonucleotidase CD73, which converts adenosine monophosphate to immuno-inhibitory adenosine, expressed by CD8+ and CD4+ T cells, was significantly upregulated in cancer patients compared to that in healthy individuals (Fig. 2g, P = 0.022 and P = 0.0001, respectively, Welch’s t-test). Here, CD4 is linked to cancer.