P-0034EXPRESSION AND CLINICAL SIGNIFICANCE OF CD9 AND MTA1 IN GASTROINTESTINAL STROMAL TUMOR

Background: To investigate the expression and clinical significance of CD9 and MTA1 in gastrointestinal stromal tumor (GIST). Methods: The expression of CD9 and MTA1 protein was detected by using immunohistochemical techniques (S-P) in 40 GIST patients and the relationship between the expression and clinico-pathologic features, risk classification and prognosis were analyzed. Results: Positive staining of CD9 was found in 60.0% of the patients. CD9 expression was not found to be correlated to any of the clinical parameters and risk classification. But, there was a statistical significant difference (79.2% vs 43.8%, P = 0.021) in post-operation 3 years recurrence-free survival (RFS) between negative patients and positive patients. Position staining of MTA1 was found in 35.0% of the patients. Positive rate of MTA1 expression was significantly higher in high risk patients than that in low / intermediate risk patients (57.7% vs 21.4%, P = 0.028). The positive patients had a lower post-operation 3 years RFS compared to the negative patients (44.4% vs 81.8%, P = 0.014), Cox regression analysis (P = 0.014, OR = 5.989, 95%CI: 1.429-25.095) showed MTA1 was an independent prognostic factor. Conclusion: The expression of CD9 and MTA1 are associated with the recurrence or metastasis of GIST patients, which may predict that they may play an important role in malignant biological behavior and metastasis of GIST.