A Study on the Expression of CD44s and CD44v6 in Non-Small Cell Lung Carcinomas

Oh, Tae Yun; Chang, Woon Ha; Kim, Jung Tae

Abstract

BACKGROUND: CD44 is a glycoprotein on the cell surface which is involved in the cell-to-cell and cell-to-matrix interaction. The standard form, CD44s and multiple isoforms are determined by alternative splicing of 10 exons. Recent studies have suggested that CD44 may help invasion and metastasis of various epithelial tumors as well as activation of lymphocytes and monocytes. The expression pattern of CD44 can be different according to tumor types. The author studied the expression pattern of CD44s and one of its variants, CD44v6 in non-small cell lung carcinomas (NSCLC) to find their implications on clinicopathologic aspects, including the survival of the patients. MATERIAL AND METHOD: A total of 89 primary NSCLSs (48 squamous cell carcinomas, 33 adenocarcinomas, and 8 undifferentiated large cell carcinomas) were retrieved during the years between 1985 to 1994. The immunohistochemistry was done by using monoclonal antibodies and the CD44 expression for angiogenesis was evaluated by counting the number of tumor microvessels. RESULT: Seventy-one (79.8%) and 64 (71.9%) among 89 NSCLSs revealed the expression of CD44s and CD44v6, respectively. The expression of CD44s was well correlated with that of CD44v6 (r=0.710, p<0.0001). The expression of CD44s and CD44v6 was associated with the histopathologic type of the NSCLCs, and squamous cell carcinoma was the type that showed the highest expression of CD44s and CD44v6 (p<0.0001). Microvessel count was the highest in adenocarcinomas (113.6+/-69.7 on 200-fold magnification and 54.8+/-41.1 on 400-fold magnification) and correlated with the tumor size of TNM system (r=0.217, p=0.043) and CD44s expression (r=0.218, p=0.040). In adenocarcinoma, the patients with higher CD44s expression survived shorter than those with lower CD44s expression (p=0.0194) but there was no statistical significance on multivariate analysis(p=0.3298).
CONCLUSION
The expression of both CD44s and CD44v6 may be associated with the squamous differentiation in non-small cell lung carcinomas. The relationship of CD44s expression with microvessel density of the tumor suggests an involvement of CD44s in tumor angiogenesis, which in turn would help tumor growth.