The SOX9 Expression And Its Association With Clinical Pathological Factors,Prognosis In Colorectal Cancer

Objective: SRY-related high-mobility group box gen9(SOX9)is located at the long arm of human Y chromosome.SOX9 is mainly responsible for the regulation of gonadal development and other physiological functions of humans.Colorectal cancer(CRC)is one of the most common malignant tumors in the world.The incidence and mortality of CRC are still rising worldwide.Emerging studies have found that SOX9 was involved in the development of many tumors.Although some researches have shown that SOX9 may be an oncogene of CRC,its expression in CRC tissues and its clinical significance have not been shown yet.Therefore,we performed immunohistochemistry to detect the expression level of SOX9 in colorectal cancer tissues and paired adjacent normal tissues.Moreover,we analyzed the relationship of SOX9 expression and clinical pathological data,prognosis in CRC.Methods:1.Tissue samples387 human CRC tissue samples were obtained from patients who were diagnosized with CRC and underwent radical resection from 2003 to 2008 at the First Hospital of China Medical University.387 samples of matched non-tumorous adjacent tissue were also collected.All the tissues specimens were fixed and embedded by formalin and paraffin.Patients should meet the following inclusion criterion: 1.All patients underwent radical surgery for CRC,and had not received preoperative chemotherapy or radiotherapy.2.All specimens were confirmed by pathological examination.2.Experimental MethodsThe common S-P method was used for immunohistochemical staining.The paraffin-embedded specimens were sectioned,baked,deparaffinized,and dislodged the peroxidase activity.After antigen retrieval and serum closure,the specimens were incubated with a primary antibody overnight at 4°C.On the second day,the secondaryantibody and horseradish peroxidase were added dropwise.Finally,the specimens were observed under the microscope.The double semi quantitative scoring method was used following the criterion: staining intensity(0: no stain;1: weak stain;2: moderate stain.3:strong stain).The percentage of positive cell:(0: <5%;1: 5-25%;2: 26-50%;3: >50%).The staining intensity score multiplied by the positive cell percentage score as the final score,range from 0-9.3.StatisticsAll data used SPSS statistical software(version 21.0)for analysis.The expression levels of SOX9 were calculated by immunohistochemistry scores.Data were presented as mean ± standard deviation and measured by T test.The relationship between the level and clinical pathological factors of the patients was measured by non-parametric test.The survival analysis was performed using Kaplan-Meier survival analysis.P values less than0.05 was considered statistically significant.Result:1.The expression level of SOX9 in CRC tissuesSOX9 is located in the nucleus.We found that SOX9 expresses in both CRC tissues and non-cancerous tissues specimens.And the expression level was significantly higher in CRC tissues than non-cancerous tissues specimens(P < 0.01).SOX9 showed high expression level in 75.71% CRC tissues and 32.30% non-cancerous tissues specimens.Next,we detected the expression levels of SOX9 in colon and rectal cancer,respectively.In both colon and rectal cancer,the expression levels of SOX9 were significantly higher in cancer tissues specimens than non-cancerous tissues specimens.In detail,SOX9 were over-expressed in 71.35% colon cancer tissues and 79.70% rectal cancer tissues.2.The relationship between SOX9 and clinical pathological dataIn CRC,there was no significantly correlation between the expression of SOX9 and age,gender,tumor size,pT stage,lymphatic metastasis,distant metastasis,TNM stage,differentiation.Furthermore,we explored the correlation between the expression of SOX9 and clinical pathological factors in colon and rectal cancer,respectively.We found that the expression of SOX9 was not significantly associated with the clinicalpathological factors.3.The relationship between SOX9 and prognosis.Kaplan-Meier survival analysis showed that there is no significantly correlation between SOX9 expression and overall survival of CRC patients.Conclusion: SOX9 was significantly up-regulated in CRC tissues compared with non-cancerous tissues.Furthermore,SOX9 showed significantly elevated expression in colon and rectal cancer,respectively.SOX9 may serve as a diagnostic marker for CRC detection.