[Are the products of CD44 exons v5 and v6 markers for metastasis of laryngeal carcinomas?].
BACKGROUND: The transmembrane glycoprotein CD44 is referred to by many names, which are related to the polymorphism of this molecule. There are at least 10 different versions of the CD44 molecule. This polymorphism results from the insertion of extra domains into the extracellular part of the molecule and from different glycolization. These extra domains are coded by variable exons in the gene of CD44, which can be alternatively spliced. Some authors have postulated a link between expression of whole CD44 or some special molecule versions (often with the product of exon v6) on carcinoma cells and the potential of metastatic spread. The aim of our investigation was to look for this connection in larynx carcinomas. METHOD: We have tested 28 larynx carcinomas without metastases, 26 with metastases, and 20 lymph node metastases from larynx carcinomas with antibodies against the products of exon v5 and v6 in immunohistochemical studies of paraffin sections. RESULTS: In all cases we observed nearly the same staining intensity of exon v5 and v6 products. There was no significant difference between carcinomas with and without metastases or the lymph node metastases. However, a strong difference of reaction was found between the carcinoma cells of the outer proliferative tumor areas and the inner tumor areas, which were cornified in parts. Whereas the first mentioned cells generally stained very intensively, the latter showed only a slight reaction or none at all. CONCLUSIONS: In our opinion, CD44 v5 and v6 appear to be valuable markers of proliferation although we could not establish a strong connection to metastatic behavior.