Clinical Significance Of Interleukin-33 In Colorectal Cancer

Objective To discuss the expression and clinical significance of interleukin-33 in colorectal cancer tissues, and to analyze its correlation with prognosis. To study the serum soluble interleukin-33(sIL-33) level and its correlation with clinical features, and to estimate its significance in colorectal diagnosis.Methods Tissue microarray contained 98 cases of colorectal cancer tissues and 80 cases of adjacent cancer tissues. Immunohistochemistry was used to test the expression of the cases. Chi-square test was used to compare the different positive expression rates between colorectal cancer tissues and adjacent cancer tissues, and to compare different positive expression rate between patients with different clinical features. Kaplan-Meier method were used to analyze correlation between IL-33 expression and overall survival(OS). Cox proportional hazard model was used to evaluate the correlation between different clinical features and prognosis of patients. 121 patients of colorectal carcinoma with preoperative serum and clinical data were collected, the control group consists of 33 intestinal polyp patients and 81 health examination persons. The sIL-33 levels were detected using ELISA method, The receiver operating characteristic(ROC) curve and logistic regression were used to compare the diagnostic value of single or combined detection of sIL-33, CEA and CA19-9.Results The positive expression rate in colorectal cancer tissues(38.78%) was significantly lower than that in adjacent cancer tissues(63.75%), difference was statistically significant(P<0.01). The expression of IL-33 was correlated with pathological grading. The positive expression rate decreased gradually along with the increasement of pathological grading(The positive expression rate corresponding to pathological grading I, II and III were 66.67%, 36.76% and 20%, respectively, P=0.027). Kaplan-Meier method analyses demonstrated that no significant difference was found between positive and negative IL-33 patients in OS(log-rank χ2=0.3755, P=0.54). Cox proportional regression multivariate analysis showed that distant metastasis(HR=7.841, P=0.002) and advanced TNM-staging(HR=2.594, P=0.003) were independent prognostic factors of colorectal cancer. Serum sIL-33 levels were significantly higher in cancer group 172.44(108.08,321.57) pg/mL than that inintestinal polyp control group 67.31(37.72,130.44) pg/mL and health examination control group 71.73(36.80,85.53), differences were statistically significant(P<0.01). The sIL-33 levels were significantly correlated with differentiation grade and tumor location, differences were statistically significant(P<0.01). The combined detection of sIL-33, CEA and CA19-9 had higher sensitivity(80.99%), accuracy(86.38%) and area under ROC curve(0.9334) than that of single detection, and the specificity(92.11%) had a high level as well, so it has preferable diagnostic value.Conclusion The positive expression rate of IL-33 in colorectal cancer tissue was lower than that in adjacent cancer tissues, and was correlated with pathological grading. sIL-33 levels were significantly higher in colorectal cancer group than that in the control group, and were correlated with differentiation grade and tumor location. The combined detection of sIL-33, CEA and CA19-9 had high auxiliary diagnosis value for colorectal cancer, and could be considered as potential serum biomarker.