ENTPD1 and breast cancer: Additionally, analysis of online databases for breast cancer indicated a correlation between PD-L1 expression and NT5E A previous study conducted [27], specific antibody staining for CD39, CD73 (NT5E), and PD-L1 on MDA-MB-231, observing multiple double-positive populations, with the highest proportion of cells co-expressing NT5E and PD-L1.