For example, can co-treatment with combinations of flavonoids lead to more effective, synergistic suppression of PD-L1 expression, by down regulation of STAT-1 as well as by inhibition of the activation of NF-κB—both required for transcription control of PD-L1—and accordingly diminish the propensity of cancer cells to exhibit escape from immune surveillance, effectively promulgating cancer cell destruction. The gene discussed is NFKB1; the disease is cancer.