FEN1 and ductal breast carcinoma in situ: Combined FEN1 nuclear/cytoplasmic protein expression was assessed in the pure DCIS cohort, where 142 cases (33%) showed high nuclear/high cytoplasmic (H.N/H.C), 152 cases (35%) showed low nuclear/low cytoplasmic (L.N/L.C), 98 cases (22%) showed low nuclear/high cytoplasmic L.N/H.C) and 45 cases (10%) showed high nuclear/low cytoplasmic (H.N/L.C) FEN1 expression.