[Analysis of the Predictive Value of EZH2 Expression Level on the Clinical Efficacy and Long-term Prognosis of Patients with Primary Gastrointestinal Diffuse Large B-cell Lymphoma].

Objective: To investigate the predictive value of methyltransferase EZH2 expression level on the clinical efficacy and long-term prognosis of patients with primary gastrointestinal diffuse large B-cell lymphoma (PGI-DLBCL).
Methods: 161 patients with newly treated PGI-DLBCL in our hospital from August 2013 to July 2019 were selected. The expression level of EZH2 protein was detected by immunohistochemistry, and the short-term efficacy and long-term survival differences of patients with different levels of EZH2 were compared. The predictive values of EZH2 expression level on the short-term efficacy and long-term prognosis of PGI-DLBCL patients were analyzed by Log-rank test and COX risk proportional regression model. Chi-square test and Logistic regression analysis were used to analyze the influencing factors of EZH2 expression level.
Results: The complete response (CR) and overal response(OR) rates of those with high EZH2 expression were significantly lower than those with low EZH2 expression (P<0.001). The median OS and PFS of EZH2 high-level and low-level expression group was 37, 31 months and 49, 42 months, respectively. The cumulative OS and PFS rates of the high-level expression group were significantly lower than those of the low-level expression group, and the differences were statistically significant (P<0.05). The high expression levels of H3K27me3, EZH2, BCL-2, BCL-6, c-MYC were closely related to the shortening of OS and PFS, while the high expression level of Ki-67 was closely related to the shortening of OS (P<0.05), of which the high expression levels of H3K27me3, EZH2, BCL-2, and BCL-6 were independent risk factors for shortening of OS and PFS. The expression level of EZH2 was positively correlated with the expression level of H3K27me3, BCL-6, c-MYC and Ki-67 (r=0.741, r=0.837, r=0.809, r=0.772), and the high expression levels of H3K27me3, BCL-6 and Ki-67 were independent factors influencing the high expression of EZH2.
Conclusion: In patients with PGI-DLBCL, the high expression of EZH2 significantly reduces the short-term CR and OR rates, which is an independent risk factor for the shortening of long-term OS and PFS rates, and it is independently related to the high expression of H3K27me3 and BCL6.