The inflammatory and hypoxic tumour microenvironment drives the expression of the ectoenzymes CD39, CD73, and CD38 on tumors, cancer associated fibroblasts (CAFs), regulatory T cells (Treg), and myeloid derived suppressor cells (MDSCs), which catalyze the conversion of ATP and NAD+ into extracellular adenosine. The gene discussed is CD38; the disease is cancer.