Expression Analysis Of CD44 Standard Form And Its V6 Spliced Variant In Lung Carcinomas

CD44 is a family of trans-membrane glycoprotein that is widely expressed in many tissues derived from epithelial, mesenchymal, hematopoietic and mesodermal origins. CD44 protein was initially identified as a guide for lymphocyte homing, and then was found to play important roles in many physiological and pathological processes such as hematopoiesis, immune response (lymphocyte activation and homing), development, wound healing, inflammation, and tumor migration. In this study, we examined the expression of CD44s and CD44v6 in 30 lung carcinomas tissues, 3 cell lines of lung carcinomas, and 16 normal lung tissues on DNA, RNA, and protein levels, and correlated the findings with tumor stage, histological differentiation. As a result, we demonstrated that:1. CD44s expressed in kinds of lung cancer, including SSC, SCLC and adenocarcinoma.2. The expression of V6 Spliced Variant in Lung Carcinomas on RNA level appears diversity.3. The expression of CD44v6 in SCLC is very low. There was a significant difference between normal lung tissue and SCLC about methylation of CD44 promoter(p<0. 05) .4. Our results revealed the reversed pattern of CD44 gene expression in squamous cell lung carcinoma versus lung adenocarcinoma. In squamous cell lung carcinoma, the number of CD44s positive cases decreases as the grading increases, while in lung adenocarcinoma it reaches the opposite.Conclusion: The results suggest that CD44s and CD44v6 are expressed with different degree in lung carcinomas. The expression of CD44v6 in SCLC is very low and there was a significant difference between normal lung tissue and SCLC about methylation of CD44 promoter, which maybe indicated that methylation effected the expression of CD44 and CD44v6. CD44v6 is most closely associated with lung cancer, especially with SSC, which may be as an index for histological differentiation of lung cancer.