CD274 and esophageal squamous cell carcinoma: However, in 57 ESCC patients without surgery, we found that EGFR and PD-L1 co-expression were statistically correlated with a lower ORR (p = 0.029) by the Chi-square test, inferior OS (p = 0.018; Figure 9A) and PFS (p = 0.045; Figure 9B) by the Kaplan-Meier method and log-rank test than those with one or none positive protein.