NT5E and B-cell chronic lymphocytic leukemia: Along similar lines, CD39 (but not CD73) levels on the surface of CD4+ and CD8+ T cells have been shown to positively correlate with disease stage in two independent cohorts of 34 and 62 patients with CLL (150, 151), while CD73 downregulation has been associated with prolonged disease-free survival amongst 500 individuals with glioblastoma (154).