The potential of CD44 as a diagnostic and prognostic tool in oral cancer.

The CD44 family of molecules exists as a wide range of isoforms ubiquitously expressed on the surface of mammalian cells. The variation in patterns of CD44 expression on cancer cells has been widely studied in relation to their behaviour, and further interest has recently arisen in CD44 as a marker of the subfraction tumour cells acting as cancer stem cells in several types of tumours. This review focuses on the patterns of CD44 expression on the stem cell fraction of oral squamous cell carcinoma and on the relationship of detectably different patterns of CD44 expression to the behaviour of tumours.