Figure 1

Low active Caspase-3 levels in patient tumours results in a significantly better disease-free survival time compared with high active Caspase-3 levels in stage 2/3 CRC patients receiving 5FU-based CT. (a) TMA sections, comprises 93 patient tumours, were stained for Pro- and active Caspase-3 and scored based on extent and intensity of staining (scale bar=100 μm). (b) Protein levels were correlated to patient outcome, and patients with low ProCaspase-3 (blue) did similarly to those with high ProCaspase-3 (green). (N=93, 40 patients expressed low protein levels and 53 patients expressed high levels). (c and d) This survival pattern was observed whether patients received CT (c; N=35, 12 patients expressed low protein levels, with 2 experiencing recurrence, and 23 patients expressed high levels, with 5 experiencing recurrence) or not (d; N=58, 30 patients expressed low protein levels, with 8 experiencing recurrence, and 28 patients expressed high levels, with 7 experiencing recurrence). (e) Patients with low levels of active Caspase-3 were found to have a significantly better disease-free survival than patients with high Caspase-3 (P=0.045; N=93, 64 patients expressed low protein levels and 29 patients expressed high levels). (f) In the CT group, this effect was further emphasised and disease-free survival was again increased in patients with low active Caspase-3 (P=0.013; N=35, 23 patients expressed low protein levels, with 2 experiencing recurrence, and 12 patients expressed high levels, with 5 experiencing recurrence). (g) In the patients who received no chemotherapy this effect on disease-free survival was lost (N=58, 37 patients expressed low protein levels, with 11 experiencing recurrence, and 21 patients expressed high levels, with 3 experiencing recurrence). (h) Western blot analysis on HCT116 cell line, untreated and treated with STS, confirmed that the antibodies (cleaved Caspase-3 antibody, 9661, CST and ProCaspase-3 Antibody, HPA002643, Atlas Antibodies) only detected the active (cleaved) form of Caspase-3 and the proform, respectively. MCF7 cells were included as a negative control for specificity determination of the ProCaspase-3 antibody