More importantly, we found that hydroxygenkwanin and Ko143 significantly restored the intracellular accumulation of PhA in ABCG2-overexpressing NCI-H460/MX20 (Figure 4A, left panel) and A549-Bec150 (Figure 4B, left panel) cancer cells, as well as in ABCG2-transfected R482-HEK293 cells (Figure 4C, left panel). Here, ABCG2 is linked to cancer.