SOLUBLE CD44 AND CD44V6 SERUM LEVELS IN PATIENTS WITH COLORECTAL-CANCER ARE INDEPENDENT OF TUMOR STAGE AND TISSUE EXPRESSION OF CD44V6

Objectives: Tissue overexpression of CD44 variants, especially CD44v6, and elevated serum concentrations of soluble CD44 variants (sCD44) ha ve been demonstrated in patients with colorectal cancer and several ot her tumors. Our aim was to evaluate the clinical value of their measur ement in colorectal cancer. Methods: To examine the suitability of sCD 44 and sCD44v6 as tumor markers in colorectal cancer these parameters were analyzed in serum of patients with colorectal cancer, inflammator y bowel disease, chronic renal failure, and controls. Tissue expressio n of CD44v6 in colorectal carcinomas was investigated by reverse trans criptase-polymerase chain reaction (RT-PCR). Results: sCD44 and sCD44v 6 levels mere significantly elevated in most of the patient groups (me dians, sCD44: 330-709 ng/ml; sCD44v6: 125-160 ng/ml) compared to contr ols (sCD44: 346 ng/ml; sCD44v6: 106.5 ng/ml). No difference was seen b etween colorectal cancer patients of different UICC (Union Internation ale Contre ie Cancer) stages and between patients with CD44v6-positive or -negative primary tumors. Conclusions: sCD44 and sCD44v6 concentra tions showed no correlation to tumor burden or CD44v6 tissue expressio n. Sensitivity and specificity were low, compared to CEA. Therefore, i n our view sCD44 and sCD44v6 measurement in screening or follow-up of patients with colorectal cancer is of very little clinical value. (C) 1998 by Am. Cell. of Gastroenterology.