Clinical Application Of Plasma Cell-free DNA In Lymphoma

Part 1 Clinical significance of plasma cell-free DNA(cfDNA)concentration and integrity in patients with lymphoma before and after treatmentOBJECTIVE: To detect plasma cell-free DNA(cfDNA)levels in patients with lymphoma,and to observe the relationship between cfDNA levels and clinical features of lymphoma patients and lactate dehydrogenase(LDH)in plasma.METHODS: Sixty patients with newly diagnosed lymphoma and 107 patients with lymphoma after treatment were enrolled.Peripheral blood samples were collected as the experimental group,and peripheral blood of 93 healthy volunteers was used as the control group.Quantitative PCR was used to detect the level and integrity of cfDNA in each group.The cfDNA levels of different groups were analyzed to explore the relationship between them and the clinical features of lymphoma patients.The sensitivity and specificity of cfDNA and LDH were analyzed and compared.RESULTS: The concentration and integrity of cfDNA in patients with newly diagnosed lymphoma were significantly higher than those in patients with lymphoma after treatment;the concentration of cfDNA in patients with lymphoma after treatment was significantly higher than that in the control group,but the integrity was not significantly different from the control group.There was no significant correlation between age,gender,extranodal invasion,and the pathological type of lymphoma and the concentration and integrity of cfDNA;In contrast,ECOG score,LDH content,Ann Arbor staging,international prognostic index(IPI),B symptoms,KI-67 expression,and radiation therapy were significantly associated with cfDNA concentration and integrity before and after treatment.cfDNA concentration detection is a better predictor of lymphoma,followed by cfDNA integrity testing,and their sensitivity and specificity are superior to traditional LDH detection.CONCLUSION: In the plasma of patients with lymphoma,the cfDNA content of peripheral blood is significantly higher than that of healthy people,and is closely related to tumor burden.Therefore,this indicator is used as a potential predictor of clinical diagnosis that may help to further improve the diagnostic level and therapeutic efficacy of lymphoma.Part 2 Differences in cfDNA levels between patients with lymphoma in pre-chemotherapy and mid-chemotherapyOBJECTIVE: To study the differences in cfDNA concentration and integrity between pre-chemotherapy and mid-chemotherapy.METHODS: A total of 120 patients with lymphoma were enrolled,and peripheral blood samples from pre-and post-chemotherapy were collected.Another 90 healthy volunteers were selected as healthy controls.qRT-PCR was used to detect the concentration and integrity of cfDNA in each group.The correlation between cfDNA and clinical features was analyzed to compare the sensitivity and specificity of cfDNA and LDH.RESULTS: The concentration and integrity of cfDNA in patients with lymphoma in middle stage of chemotherapy were lower than those in patients with lymphoma before chemotherapy,but the difference was not significant(P>0.05).The concentration of cfDNA in lymphatic patients was significantly higher than that in healthy controls(P<0.05).The cfDNA integrity of the mid-chemotherapy was higher than that of the healthy control group,but the difference was not significant(P>0.05).There was no significant correlation between cfDNA concentration/integrity and age,gender,Ann Arbor stage,FLIPI,extranodal invasion,and lymphoma pathology before and during chemotherapy(P>0.05).There was a significant correlation between ECOG score,LDH content,IPI,IPS,B symptoms and cfDNA concentration and integrity,P < 0.05.cfDNA concentration and integrity detection may be an ideal indicator for evaluating the effectiveness of lymphoma chemotherapy,with higher sensitivity and specificity than that of the traditional tumor biomarker LDH.CONCLUSION: The concentration and integrity of cfDNA in patients with lymphoma is lower than that of patients before chemotherapy,so cfDNA concentration and integrity can be used as potential biomarkers for the treatment of lymphoma.Part 3 Clinical observation of rituximab combined chemotherapy in the treatment of diffuse large B-cell lymphoma and the correlation between cfDNA and curative effectOBJECTIVE: to investigate the clinical observation of rituximab combined chemotherapy in the treatment of diffuse large B-cell lymphoma and the correlation between cfDNA and curative effect.METHODS: blood samples from patients with diffuse large B-cell lymphoma admitted to our hospital from January 17,2011 to October 17,2016 were gathered,among which 34 patients received rituximab combined chemotherapy(R-CHOP)from the sample collected by the ML25435 clinical trial.The median treatment was 4.73 courses,there were 21 males and 13 females,aged 17-80 years old,median age 55 years old,Ann Arbor stage I-II 20 cases,III-IV stage 14 cases,IPI low/medium and low risk 24 cases,medium high/high risk 10 cases.The other 32 patients’ blood samples were from patients who did not enter the ML25435 clinical trial during the same period.These patients underwent conventional chemotherapy(CHOP),with a median of 4.15 courses,there were 20 males and 12 females,aged 15-79 years.The median age was 48 years old,Ann Arbor staged I-II stage 18 cases,III-IV stage 14 cases,IPI low/medium and low risk 24 cases,medium high/high risk 8 cases.Efficacy and adverse effects were assessed using the Cheson criteria and the CTCAE v4.0 criteria.Fluorescence quantification was used to detect the concentration of cfDNA before and after treatment in patients with DLBCL.RESULTS: Thirty-two patients completed CHOP,CR 18 cases(including CRu cases);PR 8 cases;SD 4 cases;PD 2 cases;Objective Response Rate(CR + PR)was 81.25%(26/32).34 patients completed R-CHOP treatment: CR in 25 patients(including CRu cases);PR in 7 patients;SD in 1 patient;PD in 1 patient;ORR was 94.12%(32/34).The ORR rates of the two treatment regimens were statistically different.The main adverse reaction was myelosuppression,and the adverse reaction rates of the two regimens were similar.The median follow-up time was 16 months(range,6-60 months),the 5-year survival rate for patients treated with the R-CHOP regimen was 59%,and the 5-year survival rate for patients treated with the CHOP regimen was 50%.The results of real-time PCR showed that the concentration of cfDNA in patients with DLBCL was significantly different before and after treatment,and the better the effect,the lower the concentration of cfDNA,and the effect of reducing the concentration of cfDNA by R-CHOP was more significant.CONCLUSION: Rituximab combined chemotherapy for treatment ofDLBCL is more effective than CHOP,and adverse reactions can be tolerated.The results were consistent with the literature.The efficacy was better in the R-CHOP group than in the CHOP group,with similar adverse events and a higher survival rate.The concentration of cfDNA is correlated with the efficacy of chemotherapy,ie the better the effect,the lower the concentration of cfDNA.Our study suggested that cfDNA can reflect the therapeutic effect to some extent,and it is also easier to monitor changes in therapeutic efficacy.