In summary, inhibiting NF-κB with propolis and its flavonoids leads to several beneficial changes: (i) modification of the tumor microenvironment and suppression of EMT; (ii) regulation of growth factor receptors and modulation of key pathways like PI3K/Akt, MAPK/ERK and Janus kinase/signal transduction in cancer cells; (iii) control of ATP-binding cassette transporters; (iv) regulation of the cell cycle, apoptosis, and autophagy; (v) changes in CSC activity and oncogene regulation; and (vi) involvement in DNA repair processes. The gene discussed is NFKB1; the disease is cancer.