HIF1A and cancer: Polyak and Weinberg reported that the suppression of the epithelial marker, E-cadherin, is a typical characteristic of EMT induction, which is a crucial regulatory mechanism of invasion and metastasis in cancer.36 Remarkably, the HIF-1A accumulation causes EMT by upregulating ZEB1 and Wnt/β-catenin,37,38 and EMT induction suppresses PD-L1 expression.39 These studies indicated that OSCC patients with low PD-L1 expression could have a poorer prognosis than those with high PD-L1 expression through HIF-1A–induced EMT.