Expression And Clinical Significance Of ERCC1and RRM1in Non-small Cell Lung Cancer At Stage Of Ⅱb/Ⅲa

Background:Lung cancer is the most common malignant tumor in the world, and there is80%to85%non-small-cell lung cancer (NSCLC). At present, the early stage NSCLC can be cured by surgery, but tumor recurrence and metastasis is still difficulty of the treatment. With the application of the third-generation chemotherapy drugs, the effect of chemotherapy significantly improved, a number of clinical studies confirmed that5-years survival rate have improved4.0%(P<0.03) in platinum-based two-drug combination adjuvant chemotherapy than only surgery. In recent years, excision repair cross-complementation group1(ERCC1) and ribonucleotide reductase subunit1(RRM1) and others susceptibility biomarkers has been widely studied. It is reported that stage Ⅰ patients received only surgry by R0rescetion have the benifit of ERCC1and RRM1mRNA and protein high expression. It is interesting that patients got chemotherapy, especially gemcitabine plus platinum chemotherapy, have the benifit of ERCC1, RRM1mRNA and protein low expression. Due to technology constraint, most scholars abroad study the relationship of NSCLC chemotherapy drug resistance and ERCC1, RRM1mRNA. It is few study of ERCC1and RRM1protein, maybe most scholars believed that gene and protein expression are consistent. In practice, Zheng’s research shows RRM1mRNA and protein are consistent, but not are ERCC1mRNA and protein. But it is still need to explore which detection is better and suitable for clinical practice. Real-time quantitative reverse transcription polymerase chain reaction,(RT-qPCR) and automated immunohistochemical are used to detect expression of ERCC1and RRM1in Ⅱb/Ⅲa NSCLC, and analysis the correlation of mRNA and protein expression. Analysis the expression of ERCC1and RRM1with disease free survival(DFS), to find out which detection is more suitable for NSCLC prognosis.Objective:Review stage Ⅱb/Ⅲa NSCLC patients’clinical characteristics and surviva. Explore some biomarkers which can predict the efficacy of adjuvant chemotherapy, recurrence risk and prognosis. Provide a theoretical basis for establishing individual mode of adjuvant therapy after operation in NSCLC, supporting the study of gene and protein biomarkers in NSCLC adjuvant chemotherapy.Methods:The stage Ⅱb/Ⅲa NSCLC patients in our hospital received lung cancer radical surgery in March2008to December2010were analyzed with pathology and follow-up data. Collected all cases’specimens of tumor tissue and then used RT-qPCR and Leica BOND-MAX Automatic immunohistochemistry to detect ERCC1and RRM1mRNA and protein expression. Analyse the influence by patients’clinical characteristics, pathology, adjuvant treatment, ERCC1/RRM1mRNA and protein expression to DFS. SPSS13.0software is used to analyse the patients’clinical characteristics, pathology, adjuvant treatment with ERCC1/RRM1mRNA and protein expression by chi-square test, and their survival regular pattern analyzed by univariate and multivariate analysis. Results:There are198cases of stage Ⅱb/Ⅲa NSCLC eligible, the clinical and treatment characteristics are distribution regularly.(1) ERCC1and RRM1mRNA expression in different gender, smoking status, differentiation, stage showed no significant difference. But ERCC1and RRM1mRNA expression in squamous cell carcinoma, adenocarcinoma, and other types of tumors express a significant difference (ERCC1mRNA expression were58.8%,50%,23.5%, P=0.042. RRM1mRNA expression were74.5%,38.7%,44.4%, P<0.001). ERCC1with RRM1mRNA common high expressed in35/163cases (21.47%), as low expressed in42/163cases (25.77%). There is no significant correlation with ERCC1mRNA and RRM1mRNA expression in NSCLC tissues(rs=0.075, P=0.338).(2) ERCC1protein high expressed in110/190cases (57.9%) with the nucleus brown particles colored in NSCLC tumor tissue. RRMl protein high expressed in90/190cases (47.4%) with the cytoplasm brown particles colored in NSCLC tumor tissue. Which ERCC1with RRM1protein common high expressed in66/190cases (34.7%), common low expressed in56/190cases (29.47%). ERCC1protein high expressed in male patients than female (64.5%vs46.4%, P=0.022). RRM1protein high expressed in non-smokers than smokers(59.2%vs39.5%, P=0.011). Positive correlation of ERCC1and RRM1protein expression in NSCLC tissues, but there is no closely related (rs=0.297, P<0.001).(3) There is no significant correlation with ERCC1mRNA and protein expression in NSCLC tissues(rs=0.135, P=0.081). Positive correlation of RRM1mRNA and protein expression in NSCLC tissues, but there is no closely related (rs=0.181, P=0.014).(4) Follow-up to January17,2012, the disease free survival ranged from2to36months for all patients, the median disease free survival was15months. There are120cases (60.6%) advanced, median disease free survival was10.0months. There are16cases death, median disease free survival was8.5months, median overall survival was12.5months. The univariate Kaplan-Meier analysis show pathology (squamous vs adenocarcinoma vs other pathology, median DFS21months vs17months vs5months, P=0.003), stage (Ⅱb vs Ⅲa, median DFS20months vs16months, P=0.039), ERCC1protein expression (low expression vs high expression, meidian DFS20vs15months, P=0.021) were affected disease free survival significantly. Age, gender, smoking status, differentiation, adjuvant treatment, ERCC1mRNA, RRM1mRNA and RRM1protein expression had no significant impact on disease free survival.(5)In subgroup analysis, ERCC1protein low expression have a survival benefit in the adjuvant chemotherapy group than high expression (median DFS20vs15months, P=0.016). RRM1protein low expression (median DFS17vs9months,P=0.049) got a survival benefit in the gemcitabine plus platinum adjuvant chemotherapy group.(6)There are56cases(29.47%) of ERCC1with RRM1protein low expression patients in all Ⅱb/Ⅲa NSCLC candidates. ERCC1with RRM1protein low expression patients disease free survival was significantly prolonged compared with other patients (median DFS21vs16months, P=0.009). There are46cases(28.93%) of ERCC1with RRM1protein low expression patients, and they are also got such benefit (median DFS23months vs16months, P=0.013) in the adjuvant chemotherapy group. ERCC1with RRM1protein low expression patients in the gemcitabine plus platinum adjuvant chemotherapy group also got such benefit (median DFS20months vs12months, P=0.031).(7)Cox regression model for multivariate analysis showed differentiation, pathology, ERCC1protein expression as independent prognostic factor for DFS (P value all less than0.05), stage may be potential independent prognostic factors for DFS (P=0.052).Conclusion:(1) ERCC1/RRM1mRNA expression and protein expression are not closely related in NSCLC patients at the stage of Ⅱb/Ⅲa. ERCC1and RRM1protein expression are predictive factors in Ⅱb/Ⅲa NSCLC, while ERCC1and RRM1mRNA expression are not. ERCC1and RRM1protein low expression is sensitive in gemcitabine and platinum adjuvant chemotherapy.(2) ERCC1with RRM1protein low expression can got benefit from gemcitabine plus platinum adjuvant chemotherapy, it is a prognostic factor of NSCLC.