The Expression And Clinical Significance Of ERCC1, TS And EGFR In Colorectal Cancer

The expression and clinical significance of ERCC1, TS and EGFR in Colorectal CancerIntroductionTissue microarray/tissue chip is to arrange much tiny tissue on the same carrier to form a demagnification of tissue according to preliminary plan or research demand. It has small volume but much information. It is suitable for immunohistochemistry and hybridization of DNA or RNA. It largely improves experimental efficiency, and its result is reliable uniform and highly comparable. These years, tissue chip technology has been widely used in many fields, especially in clinical oncology diagnosis and research.Colorectal cancer is a familiar malignant gastrointestinal tumor which seriously threatens people's health. The treatment of Colorectal cancer is a combination composed of surgery, chemotherapy, radiotherapy and molecular targeted therapy. Multidrug resistance(MDR) is an important effective factor in the chemotherapy of colorectal cancer. The regimen of FOLFOX is an international standard combination chemotherapy regimen, but its efficiency is only 25 percent. The rate of MDR is still high. Data suggested that cetuximab(C225) associated with FOLFOX4 largely improved the efficiency of chemotherapy and reversed MDR, and brought hope for the treatment of colorectal cancer.Excision repair cross complementing 1(ERCC1), thymidylate synthase(TS) was the MDR markers of 5-Fluorouracil(5-Fu) and Oxaliplatin(L-OHP) respectively. Epidermal Growth Factor Receptor(EGFR) was the target of C225. But the mechanism of TS, EGFR, ERCC1 in MDR in colorectal cancer was not clear. Researches on combination determination of ERCC1, EGFR and TS were rare, and there was no report on the relationship between their expression and clinicopathological parameters both in domestic and foreign countries. Now clinical treatment mostly depended on experience. The combination markers determination of MDR and prognosis of much value was still scarce, which is an urgent problem to be solved.In this study, we detected the expression of ERCC1, TS and EGFR by using tissue chip technology and immunohistochemical SP methods to investigate the expression, as well as to study the correlation with clinicopathological parameters in human colorectal cancer and significance.Materials And Methods1. Patients and samplesCollecting 133 postoperative paraffinum samples of colorectal cancer from the first affiliated hospital, China Medical University (CMU) and Liaoning Province Oncology Hospital. None of them underwent chemotherapeutics or actinotherapy before operation. All the cases included 76 male and 57 female with median age of 55.4 years, ranged from 31 to 81 years. All samples were adenocarcinoma. Normal colorectal tissue of 16 samples was selected as controls.2. MaterialsThe monoclonal mouse anti-human antibody against ERCC1 was purchased from NeoMarkers Biotechnology, Inc. The monoclonal antibodies against TS and EGFR and SP immunohistochemical kits and DAB substrate solution were purchased from Fuzhou Maixin Biotechnology, Inc.3. MethodsImmunohistochemical staining SP method was performed. Slides of ERCC1 were treated with 0.01 mol/L citric acid buffer (PH=6.0) to recover the antigen activity in microwave oven, slides of EGFR were treated with pepsase to recover the antigen activity in 37℃incubation box, TS needn't recover the antigen. Tissue chip was made in Shanghai supercore Biotechnology, Inc.4. AssessmentPositive staining of ERCC1 were palm yellow particle in cytosol and nucleus, Positive staining of EGFR and TS were palm yellow particle in cytosol. Tumor tissues were counted the positive cells of 5 random images at high magnification(400×). positive cells≤10% as negative (-),＞10% as positive(+). 5. Statistical analysisstatistical methodsχ~2 test, Spearman rank correlation test were performed by SPSS software version 11.5.Results1. Expression of ERCC1 in patients with colorectal cancerThe positive expression of ERCC1 was 71.4% in 133 colorectal cancer cases and 37.5 % in normal colorectal tissue. The positive expression of ERCC1 in colorectal cancer tissue was higher than that in normal tissue. There was significant statistical difference between them (P=0.006).2. Expression of TS in patients with colorectal cancerThe positive expression of TS in 133 cases was 58.6%, however, was negative in 18 cases normal tissue.3. Expression of EGFR in patients with colorectal cancerThe positive expression of EGFR in 133 cases was 59.4%. EGFR was also expressed in normal colorectal tissues, and the positive expression was 18.75 %. The positive expression of EGFR in colorectal cancer tissue was higher than that in normal tissue. There was significant statistical difference between them (P=0.002).4. The relationship between expression of ERCC1, TS and EGFR and clinicopathologic parameters in patients with colorectal cancerThe positive expression level of ERCC1 was significantly higher in well-moderated differentiation adenocarcinoma than those in poor differentiation adenocarcinoma (P=0.025), but it didn't correlated with age, sex, part, degree of invasion or lymph nodes metastasis. The positive expression levels of TS and EGFR were significantly higher in those with lymph nodes metastasis and clinical stages ofⅢandⅣthan those without lymph nodes metastasis and clinical stages ofⅠandⅡ(P＜0.05), but it didn't correlated with age, sex, part, degree of invasion or tissue differentiation.5. The relationship between ERCC1, TS and EGFRThere was positive correlation between the expression of ERCC1 and TS (r=0.217, P=0.012). But no relationship was founded between the expression of ERCC1 and EGFR or TS and EGFR.Conclusion1. The positive expression levels of ERCC1 and EGFR in colorectal cancer tissue were higher than those in normal tissues. The positive expression of ERCC1 was associated with tissue differentiation. The positive expression levels of both TS and EGFR were associated with lymph nodes metastasis and clinical stages. None of them was associate with age, sex, part or degree of invasion.2. There was positive correlation between the expression of ERCC1 and TS.