Evaluation of CD44 and CD44v6 in colorectal carcinoma patients: soluble forms in relation to tumor tissue expression and metastasis.

INTRODUCTION

It has been shown that CD44 may be associated with poor prognosis in various human malignancies. This study was designed to investigate and compare the prognostic relevance and clinical value of soluble forms of CD44 and its variant v6 (CD44v6) and their tissue expression in colorectal carcinoma.

MATERIALS AND METHODS

Serum levels of pre- and postoperative CD44 and CD44v6 molecules were evaluated in 37 colorectal cancer patients and compared to healthy individuals.

RESULTS AND DISCUSSION

The serum levels of soluble CD44 and CD44v6 showed no significant decrease after surgical resection of the tumor (p = 0.5). Both CD44 and CD44v6 serum levels either before or after surgery were significantly higher in patients than in normal individuals (p < 0.001). The serum level of CD44v6 molecule was higher in patients with lymph node metastasis than other patients (p = 0.05) implying the role of this molecule in tumor progression. Immunohistochemical staining showed expression of CD44 in 14.3% and CD44v6 in 42.9% of the tumor samples. The expression of CD44v6 was associated with metastatic involvement of lymph nodes (p = 0.03). CD44v6 expression was positively correlated with its level in the serum of patients (p = 0.04).

CONCLUSIONS

Results of this study showed that CD44v6 expression level either in the soluble form or in the cell membrane is associated with tumor metastasis indicating the importance of this molecule in progression of colorectal carcinoma. The serum levels of soluble CD44 as well as CD44v6 might be useful markers for tumor screening.