CUL4A and lung cancer: We first investigated the expression of Cul4A in lung cancer cell lines and found that overexpression of Cul4A was noted in six lung cancer cell lines (H322, H460, A549, H838, H157 and H1703) out of eight cell lines compared to the expression of Cul4A in a normal lung cell line (WI‐38) (Fig. 1A).