Soluble protein encoded by CD44 variant exons 8-10 in the serum of patients with colorectal cancer

Clinical application of functional glycoproteomics - dissection of glycotopes carried by soluble CD44 variants in sera of patients with cancers

We provide here an example of clinical application of functional glycoproteomics for cancer diagnosis. Sialyl Lewis a and sialyl Lewis x glycotopes, which are the specific ligands for selectins, and variant forms of CD44, which are the adhesion molecules recognizing hyaluronate, are both implicated in cancer metastasis. The CD44 variants modified by the sialyl Lewis a and sialyl Lewis x glycotopes are expected to have dual functions, serving as ligands for vascular selectins, and simultaneously having binding activity to vascular bed hyaluronate, and are expected to figure heavily in cancer metastasis. We developed a heterogeneous sandwich assay system to detect soluble CD44v specifically modified by the cancer-associated sialyl Lewis a/x glycotopes, using the extracellular domain of CD44v cleaved by the metalloproteinase ADAM10 as standard molecules. We also developed the assay system for CD44v modified by normal epithelial glycotopes including disialyl Lewis a and sialyl 6-sulfo Lewis x. The results indicated that serum levels of soluble CD44v modified by cancer-associated glycotopes were frequently increased in patients with cancers, while those of CD44v modified by the nonmalignant glycotopes tended to be elevated in patients with benign disorders.

Levels of v5 and v6 CD44 splice variants in serum of patients with colorectal cancer are not correlated with pT stage, histopathological grade of malignancy and clinical features

AIM: This study was designed to compare the levels of v5 and v6 splice variants of CD44 evaluated using ELISA test in the serum of patients with colorectal cancer in different stages of progression of the disease estimated in pT stage according to WHO score, histopathological grade of malignancy and some clinicopathological features.

METHODS: The serum obtained from 114 persons with colorectal adenocarcinomas was examined using ELISA method. pT stage and grade of malignancy of the tumour were examined in formalin fixed and paraffin embedded materials obtained during operation.

RESULTS: Only the level of CD44 v5 in the serum of patients before operation with G2 pT4 tumour was lower than that in other probes and the difference was statistically significant. We did not find any other correlations between the level of v5 and v6 CD44 variants and other evaluated parameters.

CONCLUSION: The level of CD44 v5 and v6 estimated by ELISA test in the serum can not be used as a prognostic factor in colorectal cancer.