In contrast to in vitro experiments on flavonoid polyphenols summarized in Table 1 showing that induced tumor PD-L1 is suppressed by pharmacologic-achievable concentration of flavonoids, we observed copious upregulation of PD-L1 in certain cancer cells by ≥IC50 supra-pharmacological dose of polyphenol resveratrol and piceatannol, alone and combined [19]. This evidence concerns the gene CD274 and neoplasm.