The Expression Of Rac1 In The Squamous Cell Carcinnoma And Adenocarcinoma Of The Lung

IntroductionLung cancer is one of the most common malignant tumors in the world. Its mortality rate is highest among the malignant tumors in many areas in China. Invasion and metastasis is one of the most important biological feature of lung cancer and the key factor for survival of patients.The prognosis of lung cancer patients has been improved by the standardizations of surgical techniques and the application of multimodal adjuvant therapy, but there ho effective molecular markers for biological behavior diagnosis. Up to now, much research has been completed to find some molecular markers and establish the;standard of molecular classification, which may be useful for surgical therapy of lung cancer. Using immunohistochemistry S - P method and RT -PCR technique, the expression of the Racl was tested in lung cancer and para — carcinoma,then interaction relationship between;the relation and clinical -pathological features in lung cancer was investigated to apply object and useful guideline in diagnosis for the biological behavior, therapy and prognosis in lung cancer.Materials and methodsImmunohistochemistry S - P method and RT - PCR technique were used to test the expression of Racl in lung cancer and para — carcinoma. All tissue samples were collected from the first clinical academy of China Medical University. 80 cases of primary lung cancer and 30 para - carcinoma were selected, including 38 squamous cell carcinoma and 42 adenocarcinoma ones. For immunostai-nny, streptavidin peroxidase method was used, the first antibody was Racl, which was produced in Santa Crutz Co. in American. The S - P kit was purchased from Fuzhou Maixin biocompany. The section were dewaxed, water processed and then treated by 3% hydrogen peroxide in methanol for 10 minutes to quench the endogenous peroxidase activity. The sections were incubated for 30 minutes with normal non - immuneserum to eliminate non - specific staining. They were incubated at 4X1 with primary antibody. This was followed by incubation with biotin - labelled contrary antibody for 30 minutes and streptavition -peroxidase complex for 30 minutes. The color was developed with diaminobenzi-dine and the sections were counterstained with harmatoxylin. The blank control was carried out by replacing the primary with PBS. The extent of staining was scored as ( - ) , ( + ) indicating < 25 % of tumor area stained;( ++ ) 26—75 %;( +++ ) ^76%. The statistical methods were according to test x test an^ correlation analysis.The neoplastic tissues were collected and separately subject to RT - PCR a-nalysis with primers specific for Racl.Result1. The expression of Racl by immuno - histochemistryThe expression of RaclGTPase was localized in cytoplasm, and brownish yellow granule could be observed. There were no or low expression in para -carcinoma. The positive rate of lung cancer was 65 % , the rate of well differentiation lung cancer is 57 % , and rate of the poor differentiation lung cancer was 81 % , there were significant different in statistics (P=0.04<0.05). The positive rate of sex, age, stage of clinical pathology and lymph node metastasis were no significant difference.2. RT-PCRThe expression of mRNA of Racl in the lung cancer was higher than it in para — carcinoma( P < 0. 05).Discussion1. The relationship between the RaclGTPase and lung cancerThe recent research suggest that racl is a kind of RhoGTPase, which was proved to be high expression in many human tumor, and no or low expression in normal tissue. Our research draws the same conclusion.2. The relationship between the expression of RaclGTPaseThe potential carcinoma cell invasion and metastasis is concerned with the amount of Racl from lung cancer . The result of our research indicates that the positive rate of the poor differentiation is higher than the well one, and the high expression of Racl is related to the differentiation degree of the tumor, instead of the age, gender, stage of clinical - pathology and lymph node metastasis. The result of the immuno - histochemistry is not the same as the result of RT - PCR. the reason is perhaps that the cases of the study is only 30, the mount is not large enough to stead of the whole cases.ConclusionThe expression of racl in lung cancer is higher than the expression in para- carcinoma, and the expression is concerned with the different degree oftumor, Racl might be a important protein in invasion and metastasis of lungcancer, and its expression is not related with the tissue type,the age, gender,stage of clinical — pathology and lymph node metastasis.