FEN1 and neoplasm: Conversely, FEN1 overexpression resulted in a statistically significant increase in tumour cell viability compared with the 22Rv1‐Ctrl (78.12 ± 1.34 vs. 54.7 ± 1.89, p < 0.0001) and LNCaP‐Ctrl groups (83.15 ± 2.99 vs. 62.64 ± 2.18, p < 0.0001) (Figure 2A,B).