Correlation Between Galectin-3 And CEA In Pleural Effusion In Lung Adenocarcinoma With Pleural Metastasis

Objective:Carcinoembryonic antigen (CEA) is an important member of immunoglobulins,which is involved in promoting cell adhesion inhibiting cell death, mediating signal transduction and stimulating tumor immunity. In addition to gastrointestinal cancer, there is a certain degree of increase in breast cancer, lung cancer and other malignant tumors. CEA research shows that the average level in lung cancer patients is increased significantly, especially in lung adenocarcinoma. And it is earlier and more obvious in pleural effusion caused by lung cancer.Galectin-3 is a member of a large family ofβ-galactoside-binding animal lectins. It is multifunctional and involved in a variety of biological events including interactions with galactose-containing glycoconjugates, cell growth, proliferation, differentiation adhesion, apoptosis, angiogenesis, immunity response, tumor progression and metastasis and so on.. In recent years, many investigasions have discovered that galectin-3 was overexpression in different meoplasms, the level of galectin-3 expression plays an important role in tumor invasion and metastasis. Studies found galectin-3 always was overexpression in lung cancer, but seldom studies focus on the correlation between galectin-3 and pleural metastasis in lung adenocarcinoma. Present study was performed to measure the expression of galetin-3 and CEA in adenocarcinoma with metastasis of pleural, and investigate the correlation between galectin-3 and CEA in pleural effusion in lung adenocarcinoma with pleural metastasis.Methods:Thirty-four adenocarcinoma metastatic of pleural specimens were cellected from Shandong provincial hospital.Serum and pleural cotents of carcinoembryonic antigen (CEA) were determined with RIA in 34 patients in lung adenocarcinoma with pleural metastasis.ImmunohistochemistryStreptavidin-Peroxidase(SP)staining was used to detect the expression of galectin-3.CEA:It is normal when CEA is below 5ng/ml, while it is positive when above it.The ratio of CEA in pleural effusion to those of serum is positive when above one.In each case the immunohistochemical analyses consisted of an evaluation of the percentage of tumor cells stained(<25%=1; 26%-75%=2;>76%=3) and the intensity of staining(no staining=0; weak staining=1; moderate staining=2; strong staining=3). An IP score (ie Intensity×Percentage) was used to determine the overall galectin-3 expression patterns in each primary tumors and the pleural metastasis. The location of galectin-3 in cells(nuclear and/or cytoplasmic staining)was also ascertained.All the statistical analyses were carried out using SPSS 17.0, the significance of different groups were evaluated by means ofχ2 test or the exact Fisher's test and P<0.05 was considered statistically significant. Non-normal data is tested by using the Wilcoxon rank sum test. CEA data is expressed with median.Results1. In 34 adenocarcinoma metastatic of pleural specimens the positive expression of carcinoembryonic antigen (CEA) in pleural effusion and serum were 91.2%and 64.8%. The level of carcinoembryonic antigen (CEA) was higher in pleural effusion than that in serum in 30 adenocarcinoma metastatic of pleural specimens.2. The location of galectin-3 expression were in cytoplasm and nuclear. While the main pattern was cytoplasmic. No cases with exclusive nuclear immunostaining were observed. 3. In adenocarcinoma metastatic of pleural specimens the positive expression of galectin-3 in cytoplasm and nuclear were 97.1%(33/34) and 85.3%(29/34) respectively. Neither the cytoplasm staining nor nuclear staining were statistically significant between the group without lymphadenectasis and the other group with lymphadenectasis(P=0.382,P=0.059). In the cases of pleural metastatic adenocarcinoma,28 cases were poorly differentiated and 6 cases were moderately differentiated. There were also no discernible difference between moderately and poorly differentiated adenocarcinoma(P=0.389,P=0.433).4. In adenocarcinoma metastatic of pleural specimens there is 31 cases with positive expression of CEA in in pleural effusion, of which 30cases with positive expression of galectin-3 in cytoplasm are involved. While in 33 cases of positive expression of galectin-3 in cytoplasm, the positive expression of CEA in pleural effusion and serum are 30cases and 21 cases respectively.That is to say, there is a good correlation between galectin-3 and CEA in pleural effusion in lung adenocarcinoma with pleural metastasis.Conclusions:Galectin-3 and CEA express highly in adenocarcinoma metastatic of pleural specimens. Nuclear expression of galectin-3 can enhance the invasive and metastatic potential of lung adenocarcinoma, and it may be used as a biological marker of pleural metastasis in the future. There is a good correlation between Galectin-3 and CEA as for adenocarcinoma with pleural metastasis.