The observations in these studies include: (1) the elevated expression of LPHN2 and LPHN3 in breast cancer tissues, compared with normal breast tissues [21]; (2) elevated ADGRL3 expression in acute myeloid leukemia cell lines possessing P-glycoprotein variants that are linked to chemoresistance [20]; (3) higher sensitivity to a chemotherapeutic agent cisplatin in gastric and colonic cancer cells with methylated ADGRL2 [19]; and (4) an association of reduced ADGRL3 expression in tumor tissues with shorter overall survival in patients with ependymoma [22]. Here, ABCB1 is linked to ependymoma.