The Correlation Between The Intensity Of Cap43 Expression In Serum And Tissues Of Patients With Lung Cancer

The correlation between the intensity of Cap43 expression in serum and tissues of patients with Lung cancerIntroductionCap43 gene was a new gene which had a characteristic of amino acid sequence TRSRSHTSEG repeat three times in its C-terminal, and it also expressed increasedly in a large number of tumor tissues, Once the mRNA and protein was induced, their existence will be sustained and stable. Previous studies by immunohistochemistry and Western blot have found that the Cap43 protein expressed highly in human lung adenocarcinoma and glioma tumor tissue, but very lowly or no expression in normal cells or tissues. The remarkable overexpression of Cap43 protein makes it an extremely valuable marker for tumor tissues, staining with Cap43 antibody allows one in many instances to indentify cancer tissues from normal tissue. There is also the possibility of Cap43 protein being present in serum and it might be elevated in patients who have cancer. Thus, the elevation of Cap43protein in human serum may be utilized as a test for early cancer detection. We adopt a quantitative serological detection method-ELISA based on these merits of its high sensitivity, specificity, collecting samples easily for testing. The expression of Cap43 detected by sandwich-ELISA in 15 cases of lung cancer significantly greater than the normal control group (P＜0.001) and that the expression of this protein in lung adenocarcinoma was significantly higher than lung squamous cell carcinoma (P＜0.01). At the same time we found the same trend with that of serological test by adopting immunohistochemical technique in tumor tissues of lung cancer. ObjectiveTwo methods involved ELISA qualitative determination and immunohistochenmical stain were used to examine the content of Cap43 protein in serum and tissues of lung cancer patients, and the correlation between the intensity of Cap43 expression in serum and tissues and tumor histological pattern in Lung cancer was investigated.Methods1,To abtain an anti-Cap43 polyclonal antibody;2,To develop a double antibody sandwich ELISA for qualitation and quantitation determination the content of Cap43 protein in serum of lung cancer and 91 specimens were detected by this method in both lung cancer patients serum and non-lung cancer patients serum;3,83 specimens were immunohistochemically stained using an antibody(NDRG1 antibody) against antiCap43 antigen in patient s with Lung cancer.Results1,The titer of the rabbit polyclonal antiserum against human Cap43protein which was purified by caprylic acid-ammonium sulfate precipitation was 1: 500.2,The optimal concentration of the first coating antibody-goat anti-human Cap43 polyclonal antibody(PcAb), the first antibody-rabbit anti-human Cap43 and HRP-second antibody-goat anti-rabbit Cap43 PcAb were 1: 750, 1: 1200, 1: 350. The standard protein curve regression equation was:y=0.53566+0.00046x; its linear detection was 10 to 3000 ng/ml(R~2=0.9939, P＜0.0001). The intial quantitatibve detection showed the level of Cap43 protein expression in serum in lung cancer group was higher than healthy adults group(P＜0.01). The contents of Cap43 protein expression in serum in lung adenocarcinoma group were more than lung squamous carcinoma(P＜0.01).3,The S-Pimmunochemical also suggested that the Cap43 expression in the patient groups of adenocarcinoma was increased significantly compared with the groups of squamous cell carcinoma(P＜0.05).ConclusionsA sensitive, repeatable double antibody sandwich ELISA was established for quantitation of Cap43 protein in serum. The intial detecting results reveal Cap43 protein is high expressed in serum from lung cancer patients and the level of the protein expression in serum in lung adenocarcinoma is higher than lung squamous carcinoma. It is suggested that Cap43expression in both serum and tissues is closely correlated with the tumor histological pattern in Lung cancer.