HIF1A and neoplasm: Table 1 presents the correlations between PD-L1 expression in OSCC specimens and clinicopathological characteristics of patients: the low PD-L1 expression group markedly correlated with the Y–K classification; tumour infiltration; high 18F-FDG-uptake; high expression of HIF-1A/GLUT1; low levels of CD8, TILs and Ki-67 and negative expression of E-cadherin (Fig. 3a) compared with those of the high PD-L1 expression group (Fig. 3b; Table 1).