Correlation Between DNA Repair Rates In Peripheral Blood Lymphocytes And Chemotherapy Containing Alkylating Agents For Lymphoma Patients

Backgroud&Objective: Lymphoma, ranked the 11 th causes of cancer deaths in our country, is a malignant tumor originated from the lymph nodes or extranodal tissue or organ. According to different histopathological expression, lymphoma is divided into Hodgkin’s lymphoma(HL) and non-Hodgkin’s lymphoma(NHL). In China, the incidence of NHL is far higher than the HL. Chemotherapy is the main treatment of NHL.Chemotherapy containing alkylating agents are widely used in the treatment of NHLand made effective and reliable. Chemotherapy is a systemic treatment. It kills not only tumor cells, but also a lot of normal non-tumor cells, resulting in serious side effects and decreased quality of life of patients. Thus prediction of drug sensitivity and efficacy of individualized treatment of cancer has become an important part.DNA repair mechanisms are started simultaneously while alkylating agents cause damages on DNA. They can protect cells against genotoxicity caused by chemotherapeutic drugs. DNA repair is extremely complex. Related genes, proteins and enzymes reflect only one or a few links.DNA repair rate(DNA repair rate, DRR) can fully reflect the individual’s DNA repair capacity and it may become the clinical predictor of the efficacy of treatment containing alkylating agents.In this study, single cell gel electrophoresis(Single cell gel electrophoresis, SCGE) is used to detect PBLC DRR of NHL patients with initial treatment. The relationship between PBLC DRR and the efficacy of treatment containing alkylating agents were analyzed, in order to provide the basis of prediction of chemotherapy sensitivity and short-term effect for NHL patients.Methods: The DRRs of PBLC in 30 patients with NHL and 20 controls without cancer were detected by single cell gel electrophoresis(SCGE). The NHL patients received chemotherapy including cyclophosphamide and the efficacy was evaluated after four cycles. In both groups, the DRRs before cyclophosphamide exposure and after exposure followed by restoration were analyzed. The correlation between the DRR of NHL group and the clinicopathological features and the efficacy of combined chemotherapy containing alkylating agents was investigated.Results: DRRs of the NHL patients were obviously lower than the controls by tail length(Z =4.464,P =0.000) and tail moment(Z=3.828,P=0.000).The DRRs have no relationship with age, gender, ECOG score, clinical stage, LDH value, ki-67 proliferationindex and drinking habits(P>0.05). In the 30 cases of NHL patients, there were CR in 4cases, PR in 14 cases, SD in 10 cases and PD in 2 cases with objective response rate(ORR) of 60.0% and disease control rate of 93.3%. To evaluate DRRs with TL(r=-0.409, p=0.025), it showed that DRRs were negatively correlated with the efficacy of chemotherapy. In addition, no relationship was found between DRRs and efficacy by TM(r=-0.224, p=0.234).Conclusion: NHL patients have lower DNA repair capacity than people without cancer.The DRR in PBLCs is correlated negatively with the efficacy of NHL patients treated with alkylating agents.