Although the number of PD-L1-positive cases was small, when we evaluated the expression in cancer cells and immune cells separately, only the non-well-differentiated type was a predictive factor of PD-L1 expression in both cancer cells (odds ratio [OR] 25.05, 95% confidence interval [CI]: 1.22–513.85, P = 0.04) and immune cells (OR 44.14, 95%CI: 1.96–995.97, P = 0.02) (Table 3). The gene discussed is CD274; the disease is cancer.