Compared with the 22Rv1‐Ctrl group, the tumour/body weight index of nude mice in the 22Rv1‐FEN1‐KD group decreased statistically significantly (p < 0.0001), while that of the 22Rv1‐FEN1‐OE group increased statistically significantly (all p < 0.0001). Here, FEN1 is linked to neoplasm.