Expression Of Ki-67 And MMP-2 In Thymoma And The Association With Clinicopathological Features And Prognosis

ObjectiveTo evaluate the expression of Ki-67 and MMP-2 in different types of thymoma, as well as to determine their potential correlation of these two factors with several clinical and pathological characteristics, and patients'survival. Thus it provided assistance to the early clinical diagnosis, pathological diagnosis, the prognosis of thymoma, and provided an objective standard of indicators for clinical diagnosis and treatment.MethodsParaffin-embedded tissue samples were retrospectively collected from 80 patients with thymic epithelial tumors and 20 patients with thymic cyst, who received surgical resection between 2003 and 2010 at China Medical University Shengjing Hospital, with a median follow-up of 44 months. We examined the expression of Ki-67 and MMP-2 by immunohistochemistry method (SP method) and followed-up the out-patients by telephone and reviewed the medical records to collect follow-up data. Statistical analysis was performed with univariate tests and multivariate Cox proportional hazards model to evaluate the differences. Therefore, we discussed their possible correlation to tumor clinicopathological parameters, progression and overall survival in thymomaResultsThe expression of Ki-67 and MMP-2 were higher in thymoma cases (30/80 and 34/80), compared to normal thymus (1/20 and 0/20), there is significant difference.The relations between Ki-67 expression and clinical pathological factors in thymoma:①WHO classification:The rate of Ki-67 positive expression increasing trend in the WHO classification; The difference among A/AB,B1-B3 and C type were significant difference (p<0.05);②Suster-Mora classification:the rate of positive expression has obvious difference (p<0.01);③Bernatz classification:The positive expression rate of epithelial cell type, lymphocyte and mixed were 65%,30.43% and 29.17%, which is significant difference (p<0.05);④Masaoka stage:the positive expression rate of StageⅢ+Ⅳ(65.52%) was significantly higher than the stageⅠ+Ⅱ(21.57%) (p<0.01);⑤Expression rate of invasive thymoma (54.35%) was significantly higher than non-invasive (14.71%), which is significant difference (p<0.01);⑥Tumor size:As the tumor increases, Ki-67 expression was also increased, and there was a significant difference (p<0.05).⑦Patient's sex, age, and MG and the Ki-67 expression was not relevant.The relations between MMP-2 expression and clinical pathological factors in thymoma:①WHO classification:The rate of MMP-2 positive expression increasing trend in the WHO classification; The difference among A/AB,B1-B3 and C type were significant difference (p<0.01);②Suster-Mora classification:the rate of positive expression has obvious difference (p<0.01);③Bernatz classification:The positive expression rate of epithelial cell type, lymphocyte and mixed were 80%,30.43% and 37.5%, which is significant difference (p<0.01);④Masaoka stage:the positive expression rate of Stage III+IV(79.31%) was significantly higher than the stageⅠ+Ⅱ(23.53%) (p<0.01);⑤Expression rate of invasive thymoma (65.22%) was significantly higher than non-invasive (11.76%), which is significant difference (p<0.01);⑥Patient's sex, age,tumor size and MG and the MMP-2 expression was not relevant.Survival analysis showed:the expression of Ki-67 and MMP-2 and survival rate significantly correlated in single-factor analysis, which assess the prognosis of patients with a certain sense; but it did not obtain positive results in multivariate analysis.ConclusionsSignificant correlation was found between the expression of Ki-67 and MMP-2 invasive thymoma, pathological type and stage of the disease. Ki-67 expression was associated with tumor size, while the MMP-2 is not.The expression Ki-67 and MMP-2 in thymoma tissue have good consistency, and there is positive correlation. The expression of Ki-67 and MMP-2 and survival rate significantly correlated, which was a meaningful assessment of the prognosis of patients. Sex, age and MG is no significant.The joint detection of both plays a significant important role in understanding the occurrence and development of the thymoma, the early diagnosis of the human thymic tumors, the judgment of their malignant degree and pathology, it provides objective basis for judging the prognosis of patients with thymoma...