| Objective: Non-Hodgkin's lymphoma is one of the malignant tumors of the blood system.Diffuse large B-cell lymphoma(DLBCL)is the most common type of non-Hodgkin's lymphoma,accounting for nearly half of adult lymphoma.It is a group of highly heterogeneous B cell invasive lymphoma,and its main treatment is chemotherapy.The rituximab combined with chemotherapy significantly improves the therapeutic efficacy of diffuse large B-cell lymphoma,and it's considered a standard treatment regimen.However,even with the standard protocol,nearly 40% of patients will ultimately relapse or progress.The etiology and genomics analysis of diffuse large B-cell lymphoma provides a new direction for early diagnosis,targeted therapy and prognostic assessment.The development of diffuse large B-cell lymphoma is the results of a multi-gene and multi-factor interaction,so the early diagnosis and treatment of molecular targets is to find and to identify the tumor-related genes.Studies have shown that the development of tumors includes at least two levels of genetic and epigenetic regulation,including oncogene activation,tumor suppressor gene inactivation and so on.And epigenetic regulation seems to play a more important role.In recent years,epigenetic phenomena have been identified in the pathogenesis of a variety of tumors,including DNA methylation,histone modification,chromatin remodeling and so on.RAS-related region family 6 gene(RASSF6)is a tumor suppressor gene.The expression of RASSF6 can inhibit the proliferation of tumor cells by co-binding with K-Ras,and can prevent cell cycle progression by activating JNK signaling pathway.In addition,through the activation of caspase pathway and other pathways,RASSF6 makes tumor cell apoptosis.Studies have shown that there're the RASSF6 gene promoter hypermethylation in childrenleukemia,gastric cancer,breast cancer and other tumors.Methylation is one of the important causes of RASSF6 gene inactivation.And RASSF6 studies in diffuse large B-cell lymphoma has not been reported.In this study,methylation-polymerase chain reaction(MSP)and real-time fluorescence quantitative reverse transcription-polymerase chain reaction(QRT-PCR)were used to verify the methylation status and expression of RASSF6 in the promoter region of diffuse large B-cell lymphoma,then analyze the relationship between RASSF6 gene with the sample data,and provide a theoretical basis for the pathogenesis,clinical diagnosis and treatment of diffuse large B cell lymphoma.Methods:1 MSP was used to detect the methylation status of RASSF6 gene in peripheral blood of diffuse large B cell lymphoma and healthy people,and analyzed the relationship between RASSF6 gene and clinical data.2 Applied QRT-PCR method to detect the relative expression levels of RASSF6 gene mRNA in diffuse large B-cell lymphoma and healthy people,and the relationship between RASSF6 gene and clinical data was analyzed.3 SPSS19.0 was used to analyze the results of experiments.Results:1 The methylation rates of the RASSF6 gene promoter region were48.6%(17/35)and 14.3%(5/35)in peripheral blood of patients with diffuse large B-cell lymphoma and healthy subjects,respectively,.The methylation rate of RASSF6 gene promoter region in patients with diffuse large B cell lymphoma was significantly higher than that in healthy people(P <0.05).2 Group analysis showed that RASSF6 methylation was associated with Ki-67,LDH and clinical stage in patients with diffuse large B-cell lymphoma(P <0.05),and was not associated with sex,age,extranodal involvment,A/B symptom,Germinal center origin(GCB)or non-germline center origin(Non-GCB),?2 microglobulin,bone marrow involvement and IPI(P> 0.05).3 The expression of RASSF6 gene mRNA in patients with diffuse large B cell lymphoma was 0.0415±0.0287,which was significantly lower than thatof healthy human(0.0634±0.0427),the difference was statistically significant(P <0.05).4 The expression of RASSF6 gene mRNA in patients with diffuse large B-cell lymphoma was correlated with IPI,Ki-67 and extranodal involvment(P<0.05),and was not associated with sex,age,LDH and A/B symptoms,GCB or Non-GCB,?2 microglobulin,bone marrow involvement,clinical stage(P>0.05).5 The mRNA expression of methylation-positive RASSF6 gene in peripheral blood of diffuse large B-cell lymphoma was 0.0306±0.0256,and the mRNA expression of methylation-negative RASSF6 gene was 0.0518 ±0.0283,the difference was statistically significant(P <0.05).Conclusions:1 The methylation rate of RASSF6 gene promoter in patients with diffuse large B cell lymphoma was significantly higher than that of healthy people,which indicated that methylation of RASSF6 gene promoter may be one of the mechanism of diffuse large B cell lymphoma.2 The expression of RASSF6 mRNA in patients with diffuse large B cell lymphoma was significantly lower than that of healthy people,suggesting that RASSF6 gene may play a role in tumor suppressor gene in diffuse large B cell lymphoma.3 The methylation rate of the promoter region of RASSF6 gene in patients with diffuse large B-cell lymphoma was negatively correlated with its mRNA expression,suggesting that methylation of RASSF6 gene promoter region may be one of the reasons of decreased in mRNA expression in patients with diffuse large B-cell lymphoma.4 The promoter methylation of RASSF6 gene in patients with diffuse large B-cell lymphoma was associated with Ki-67,LDH and clinical stage in patients,suggesting that the methylation status of RASSF6 gene promoter may be related to the invasion and prognosis of diffuse large B-cell lymphoma. |
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