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) have been demonstrated in patients with colorectal cancer and several other tumors. Our aim was to evaluate the clinical value of their measurement in colorectal cancer.

METHODS

To examine the suitability of sCD44 and sCD44v6 as tumor markers in colorectal cancer these parameters were analyzed in serum of patients with colorectal cancer, inflammatory bowel disease, chronic renal failure, and controls. Tissue expression of CD44v6 in colorectal carcinomas was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

sCD44 and sCD44v6 levels were significantly elevated in most of the patient groups (medians, sCD44: 330-709 ng/ml; sCD44v6: 125-160 ng/ml) compared to controls (sCD44: 346 ng/ml; sCD44v6: 106.5 ng/ml). No difference was seen between colorectal cancer patients of different UICC (Union Internationale Contre le Cancer) stages and between patients with CD44v6-positive or -negative primary tumors.

CONCLUSIONS

sCD44 and sCD44v6 concentrations showed no correlation to tumor burden or CD44v6 tissue expression. Sensitivity and specificity were low, compared to CEA. Therefore, in our view sCD44 and sCD44v6 measurement in screening or follow-up of patients with colorectal cancer is of very little clinical value.