USP22 and lung cancer: To further confirm the role of AP2A and AP2Β in USP22 expression, additional siRNA for TFAP2A and TFAP2Β were synthesized and transfected to H1299 (upper panel) and A549 (lower panel) cells, and the results showed that two individual specific siRNAs targeting AP2A (left panel) and AP2Β (right panel) markedly decreased mRNA expression (Fig. 4A, data of A549 wasn’t shown) and protein levels (Fig. 4B) of USP22 in H1299 and A549 lung cancer cells.