Soluble CD44: quantification and molecular repartition in plasma of patients with colorectal cancer

Based on the important role of CD44 in tumour progression and metastasis, w e evaluated, in a prospective study, plasma-soluble CD44 (sCD44) as a serum marker in colorectal cancer. Blood plasma specimens from 89 patients with colorectal neoplasm, 22 patients with a gastrointestinal disease and 23 hea lthy donors were analysed for quantitation (ELISA assay) and purification o f sCD44. The concentration of sCD44, indicating the concentration of all is oforms, was significantly higher in patients with colorectal cancer and int estinal disease than in normal individuals, but no significant differences were found between the two groups. We found no association between plasma l evels and staging of the colorectal cancer patients according to Astler and Coller. A two-step batch purification combining ion exchange and immunoaff inity chromatography, followed by Western blot analysis, revealed a complex pattern with a major band corresponding to the standard form of CD44 and m inor bands that may correspond to larger variant forms. No particular sCD44 isoform was clearly associated with anatomopathological or biological info rmation.