Structure, function and role of CD44 in neoplasia

CD44 is a group of protein molecules which perform a variety of functions. Their wide range of functions are mainly based on their multiple variations in their molecular structure. Furthermore, they are distributed in various tissues of the human body. They have a unique property of cell adhesion, which can lead to interaction between two different cells or a cell and its pericellular matrix. CD44 as a cell surface adhesive molecule helps in aggregation and migration of tumor cells. CD44 plays an important role in cancer of bladder, liver, lungs, pancreas, etc. Expression profile of CD44 has been seen in the epithelia of the lip, tongue, gingiva, hard palate, floor of the mouth, buccal mucosa and pharynx. The relationship between the expression of CD44 v6 and regional lymph node metastasis has been studied immunohistochemically. The expression of CD44 v6 was apparently downregulated in oral squamous cell carcinoma, but not in normal oral mucosa. Carcinomas expressing lower levels of CD44 v6 exhibited more frequent regional lymph node metastasis. No significant relation was found between the expression of CD44 v6 in primary and metastatic lesions. Still, the precise function of CD44 in the metastatic process and the degree of involvement in human malignancies is yet to be established.