CD8A and carcinoma of esophagus: Furthermore, a study found that in ESCC the invasion of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) promotes CD39 expression on CD8+ T cells, decreases sensitivity to chemotherapy, and consequently leads to poor prognosis [8], suggesting a potential role of CD39 expression on CD8+ T cells in the progression of esophageal carcinoma.