Similarly, 5 μM of sitravatinib also increases the accumulation of pheophorbide A (PhA), a fluorescent substrate of ABCG2 [46], in ABCG2-transfected R482-HEK293 cells (Figure 4c) and ABCG2-overexpressing S1-M1-80 cancer cells (Figure 4d). The gene discussed is ABCG2; the disease is cancer.