FEN1 and neoplasm: High FEN1 mRNA level was associated with younger patient age (p = 0.037), large tumour size (p < 0.001), high nuclear grade (p < 0.001), positive lymph node involvement (p < 0.001), hormonal receptor negativity (p < 0.001), positive HER2 status (p < 0.001) and basal-like subgroup (p < 0.001) (Supplementary Table S2).