ATP2C1 and lung cancer: To elucidate whether the differential expression of Circ_0007552 plays a functional role in lung cancer, the expression profile of Circ_0007552 was systematically examined in normal lung epithelial cells (BEAS-2B) and LUAD cells lines (A549, PC-9, SPCA1, H1299, H838, H1734, 95-D).