In this study we for the first time found that microRNA expression levels of sera miR-15a, -16, and -193a-3p were significantly down regulated (all p < 0.05) in BE PD-L1(+) patients (Figure 5); further sera miR-15a, -15b, -16, and -193a-3p expression levels in EAC PD-L1(+) patients were significantly lower (all p < 0.01) when compared to EAC PD-L1(-) patients (Figure 5). The gene discussed is CD274; the disease is Barrett esophagus.