Then, we examined the protein level of ZEB1 in different lung cancer cell lines and we found weak ZEB1 was detectable in A549 cells when given a longer exposure compared with a visible band in H1155 cells (Figure 3a), which is consistent with the previous report showing endogenous ZEB1 expression in both A549 and H1155 cells.31 Less p66Shc protein level was at least in part related to higher ZEB1 expression level (Figure 3a). Here, ZEB1 is linked to lung cancer.