Expression of Cell Adhesion Molecules -CD44H and CD44v6- in Colorectal Carcinoma

Kim, Dae Cheol; Rha, Seo Hee; Jeong, Jin Sook; Hong, Sook Hee

Abstract

During tumor progression, a subset of cells acquires metastatic properties, presumably through a series of genetic alterations. As the result, cells detach from the primary tumor, penetrate the basement membrane and invade the adjacent structures including lymph and blood vessels. Loss of adhesive functions and gain of new adhesive functions are thought to play a crucial role in this metastatic cascade. Since tumor metastasis is the principle cause of death for cancer patients including colon cancer, there is a consensus that a search for tools that allow effective assessment of the metastatic potential of tumors is a prime goal for cancer research. An immunohistochemical study of cell adhesion molecules, CD44H and its variant CD44v6, was done to evaluate their relationship with known prognostic factors related to the progression and metastasis of colorectal carcinoma in 94 cases of colorectal carcinoma tissues. The results were as follows. The CD44H expression was detected in 90 (95.7%) and CD44v6 in 53 (56.4%) out of 94 cases of colorectal carcinoma, and the CD44H was overexpressed in tumor tissue more than in normal mucosa in 62% of the cases. The expression rates of both protein were not significantly correlated with age and sex of the patients, invasion depth, lymph node metastasis, tumor differentiation, and tumor site. The coexpression of CD44H and CD44v6 in tumor was significant (p<0.05). The above results suggest that overexpression of CD44H and loss of function to control the alternative splicing of CD44 mRNA resulting in CD44v6 expression and alteration of adhesive function are closely associated with tumorigenesis of the colorectum.