Purpose To explore the molecular features of diffuse large B-cell lymphoma(DLBCL)with high expression of MYC.Methods The clinical data of 45 cases of DLBCL were collected.Immunohistochemical EnVision method was used to classify the patients into the group with high expression of MYC and the group with low expression of MYC.All samples were subjected to DNA targeted sequencing and molecular typing was performed using the LymphGen online tool.Cellular origin was determined by using the Lymph2Cx method.The correlation be-tween MYC overexpression and clinicopathological parameters was analyzed by the x2 test and Fisher precise test.Survival curves were drawn and survival-related factors were analyzed u-sing Cox univariate and multivariate regression.ResultsCases were classified into DLBCL with high expression of MYC(n=17)and DLBCL with low expression of MYC(n=28).Com-pared to the group with low expression of MYC,the group with high expression of MYC had more PIM1,MYD88,CD79B,CD58 and PRDM1 mutations(76.5％vs 28.6％,70.6％vs 32.1％,58.8％vs28.6％,29.4％vs3.6％,29.4％vs 3.6％,P＜0.05),MCD were more frequently found(58.8％vs 10.7％,P=0.001),GCB were rarely found(17.6％vs 50.0％,P=0.030).Overall survival was significantly shorter in DLBCL with high expression of MYC(P＜0.05).Cox multi-factorial analysis showed that age was an independent prognostic factor for DLBCL(P＜0.05).Conclusion Patients with high expression of MYC were frequently characterized as MCD and ABC,and PIM1,MYD88,CD79B,CD58 and PRDM1 muta-tions were common.Patients with high expression of MYC had a poorer prognosis.