| Objective Diffuse large B-cell lymphoma is a malignant disease that shows highly invasiveness and heterogeneity.The characteristics of disease are closely related to the primary site,gene variation,epigenetic modification and some other factors.The aim of this study was to retrospectively analyze the relationship between treatment strategies and the prognosis of primary intestinal diffuse large B-cell lymphoma(PI-DLBCL).And the prognostic relationship between genome-wide DNA methylation pattern and the progression free survival.Methods This study was an retrospective study.Firstly,A total of 50 PI-DLBCL patients that first diagnosed and treated in National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital were enrolled in this study.Keplan-Meier analysis and Multi-Cox regression were performed.We analysis the clinical characteristics of PI-DLBCL patients.R-CHOP combined with surgery and R-CHOP regimen alone were compared in this study.Secondly,a number of 66 cell free DNA(cfDNA)samples and 39 formalin-fixed paraffin-embedded(FFPE)samples were collected.The genome-wide DNA methylation was analyzed using the Infinium MethylationEPIC BeadChip.LASSO Cox regression,univariate analysis and multivariate analysis were used to explore the feature of methylation characteristics.A CpG based classifier were used to predict the outcome of DLBCL patients.Results The most commonly involved intestinal sites were the small bowel(40%),followed by the colon(36%),ileocecal region(22%)and rectum(2%).The 3-year overall survival(OS)and 3-year progression free survival(PFS)for the entire group were 76.0%and 65.9%respectively.ECOG PS,LDH level and surgery were independent prognostic factors for PFS.LDH level and surgery were independent risk factors for OS in PI-DLBCL patients.Immunochemotherapy combined surgery treatment was also associated with a lower rate of refractory/relapsed(R/R)disease.The study demonstrated the existence of heterogeneity between DNA methylation patterns and the prognosis in Chinese population.LASSO Cox regression revealed that there were fourteen sinificant differnet methylation CpG sites that affect PFS of DLBCL individuals.The multi-cox regression showed that fourteen CpG-based classifier,serum LDH level,Ann Arbor stage,IPI score and bulky disease were independent risk factors for PFS.A nomogram including these five independent prognostic factors showed a significantly higher predictive accuracy than each single variable both in serum cohort and tumor tissue cohort.Conclusion Clinical research and basic research methods were used in this study.The outcome revealed that in the overall population,the methylation patterns were closely associated with the prognosis of DLBCL.Immunochemotherapy plus surgery was associated with a superior prognosis compared with R-CHOP alone in Chinese PI-DLBCL population.This study is significant because of the innovative ideas provided for DLBCL patients.Part 1.The Analysis of Methylation Patterns with the Prognosis of Diffuse Large B-cell Lymphoma by Genome-wide Methylation ProfilingObjective We aims to identify diffuse large B-cell lymphoma(DLBCL)specified methylation biomarkers with circulating cell-free DNA(cfDNA)and show its association with the prognosis.We evaluated the value of CpG methylation in predicting relapse for DLBCL.Methods The genome-wide DNA methylation profiling was done by extracting the cfDNA and FFPE tissue DNA from 66 and 39 patients respectively.DNA methylation was analyzed using the Infinium MethylationEPIC BeadChip.We built a fourteen CpG classifier using LASSO Cox regression based on the methylation level and progression free survival(PFS)in the cfDNA training cohort(n=50).The fourteen CpG classifier was validated in the internal cfDNA testing cohort(n=16)and tumor tissue cohort(n=39).Multivariate Cox analysis were used to explore the independent risk factors for PFS.Results The medial age of cfDNA cohort is 55 years old.The ratio of male to female is 31:35.The medial age of FFPE cohort is 52.5 years old.The ratio of male to female is 17:22.LASSO Cox regression revealed that there were fourteen sinificant differnet methylation CpG sites that affect PFS,including cg07906520,cg20564892,cg13371456,cg15790852,cg07978591,cg09463984,cg26608795,cg08005330,cg25867318,cg03107955,cg03681057,cg17650523,cg01789705 and cg27581794.The fourteen CpG-based classifier discriminated DLBCL patients that accepted standard fisr-line chemotherapy at high risk of relapse in the cfDNA training cohort from those at low risk(p<0.0001).This classifier also showed good predictive value in the cfDNA internal testing cohort(p=0.0004)and the tumor tissue teating cohort(p=0.0110).Multi-cox regression showed that fourteen CpG-based classifier(p=1.31E-10,HR=3.32E+12,95%CI:5.03E+08～2.18E+16),serum LDH level(p=0.019,HR=2.940,95%CI:1.200～7.240),Ann Arbor stage(p=0.002,HR=1.940,95%CI:1.280～2.940),IPI score(p=0.003,HR=1.560,95%CI:1.160～2.100)and bulky disease(p=0.006,HR=3.300,95%CI:1.420～7.680)were independent risk factors for PFS.A nomogram including these five independent prognostic factors showed a significantly higher predictive accuracy than each single variable.Conclusion CfDNA is a new approach to epigenome-wide discovery of methylation biomarker in DLBCL.The fourteen-CpG-based classifier could predict the PFS in patients with DLBCLand could be used to guide treatment decision.Part 2.Clinical Characteristics and Prognostic Analysis of Primary Intestinal Diffuse Large B-cell LymphomaObjective The aim of the study was to compare the characteristic,therapeutic strategies and prognostic factors of patients with primary intestinal diffuse large B-cell lymphoma(PI-DLBCL).Methods A total of 50 PI-DLBCL patients who accepted standard first-line treatment at National Cancer Center in China were included in this retrospective study.Survival analysis was performed to evaluate the prognostic risk factors.Results The 3-year overall survival(OS)and 3-year progression free survival(PFS)for the entire group were 76.0%and 65.9%respectively.Univariate analysis showed that B symptom,advanced Lugano stage,elevated LDH status,poor ECOG PS and immunochemotherapy alone were significantly correlated with a poor PFS.Elevated LDH status,poor ECOG PS,advanced Lugano stage,high IPI score and immunochemotherapy alone were significantly correlated with a poor OS.Multivariate analysis revealed that ECOG PS(p=0.026,HR=4.768,95%CI:1.208～18.822),LDH level(p=0.007,HR=4.829,95%CI:1.528～15.263)and surgery(p=0.001,HR=0.138,95%CI:0.045～0.423)were independent prognostic factors for PFS.LDH level(p=0.029,HR=5.193,95%CI:1.183～22.809)and surgery(p=0.001,HR=0.106,95%CI:0.029～0.387)were independent risk factors for OS in PI-DLBCL.Immunochemotherapy combined surgery treatment was also associated with a lower rate of refractory/relapsed(R/R)disease(p=0.004).Conclusion Immunochemotherapy plus surgery was associated with a superior prognosis compared with R-CHOP alone in Chinese PI-DLBCL population. |
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