SOX9 Expression Predicts Relapse of Stage II Colon Cancer Patients

The aim of this study was to investigate if the protein expression of Sex-determining region y-box 9 (SOX9) in primary tumors could predict relapse of stage II colon cancer patients.144 patients with stage II primary colon cancer were retrospectively enrolledin the study. SOX9 expression was evaluated by immunohistochemistry and mismatch repair status was assessed by both immunohistochemistry and promoter hyper-methylation assay. High SOX9 expression at the invasive front was significantly associated with lower risk of relapse when including the SOX9 expression as a continuous variable (from low to high expression) in univariate (HR: 0.73; 95% CI: 0.56-0.94; p=0.01) and multivariate cox proportional hazards analysis (HR: 0.75; 95% CI: 0.58-0.96; p=0.02) adjusting for mismatch repair deficiency and histopathological risk factors. Conversely, low SOX9 expression at the invasive front was significantly associated with high risk of relapse, when including SOX9 expression dichotomous variable, in univariate (HR: 2.32; 95% CI: 1.14-4.69; p=0.02) and multivariate analysis (HR: 2.32; 95% CI: 1.14-4.69; p=0.02) adjusting for histopathological risk factors and mismatch repair deficiency. In conclusion high levels of SOX9 of primary stage II colon tumors predict low riskof relapse whereas low levels of SOX9 predict high risk of relapse. SOX9 may have an important value as a biomarker when evaluating risk of relapse for personalized treatment.