Fig 1: Effects of STN1 deficiency on CRC tumor markers, cell proliferation, apoptosis, and DNA damage in mouse colon tissue.(A) Representative IHC staining of ?H2AX showed a higher DNA damage level in STN1-/- mice. Boxed areas are magnified to show staining details. (B) IHC staining with Ki67 showed a higher cell proliferation level in STN1-/- mice. (C) TUNEL assay showed that STN1-/- mouse colon tumor displayed reduced cell apoptosis. Red arrows point to apoptotic cells. Data are shown as the relative average number of apoptotic cells per image. Scale bars, 20 µm. (D to F) IHC staining showed higher expression of tumor markers ß-catenin (D), Cox-2 (E), and c-Myc (F) in STN1-/- mice. For all IHC staining and TUNEL assays, the paraffin-embedded distal colon tissues from four pairs of mice [STN1+/+ (n = 4) versus STN1-/- (n = 4)] were processed for staining. In all IHC images, scale bars are 100 µm. IHC signals were quantified using ImageJ. At least 5000 cells were measured in each group. All signals were normalized to the STN1+/+ group, and relative intensities were graphed. Statistical analysis: two-tailed t tests. Error bars: SEM.