Unaltered strong immunohistochemical expression of CD44-v6 and -v5 isoforms during development and progression of oral squamous cell carcinomas.

The present study was designed to immunolocalize CD44-v6 and -v5 isoforms in normal, dysplastic and malignant oral mucosa as well as in primary and metastatic oral squamous cell carcinomas. Routinely formalin-fixed and paraffin-embedded tissues of 100 oral carcinoma patients were immunohistochemically investigated following wet autoclave antigen retrieval. Both CD44-v6 and -v5 epitopes were uniformly strongly expressed on the cell surface of basal and intermedial epithelial cells of normal and dysplastic mucosa and in all primary and metastatic squamous cell carcinomas with the exception of end-differentiated keratinizing cells. Our results strongly suggest that CD44-v6 and -v5 isoform expression is not altered during development and progression of oral carcinomas. Thus, they seem to be irrelevant factors in the prediction of prognosis in this type of cancer.