CD44s and CD44v6 expression in head and neck epithelia.
BACKGROUND
CD44 splice variants are long-known as being associated with cell transformation. Recently, the standard form of CD44 (CD44s) was shown to be part of the signature of cancer stem cells (CSCs) in colon, breast, and in head and neck squamous cell carcinomas (HNSCC). This is somewhat in contradiction to previous reports on the expression of CD44s in HNSCC. The aim of the present study was to clarify the actual pattern of CD44 expression in head and neck epithelia.


METHODS
Expression of CD44s and CD44v6 was analysed by immunohistochemistry with specific antibodies in primary head and neck tissues. Scoring of all specimens followed a two-parameters system, which implemented percentages of positive cells and staining intensities from - to +++ (score = % x intensity; resulting max. score 300). In addition, cell surface expression of CD44s and CD44v6 was assessed in lymphocytes and HNSCC.


RESULTS
In normal epithelia CD44s and CD44v6 were expressed in 60-95% and 50-80% of cells and yielded mean scores with a standard error of a mean (SEM) of 249.5+/-14.5 and 198+/-11.13, respectively. In oral leukoplakia and in moderately differentiated carcinomas CD44s and CD44v6 levels were slightly increased (278.9+/-7.16 and 242+/-11.7; 291.8+/-5.88 and 287.3+/-6.88). Carcinomas in situ displayed unchanged levels of both proteins whereas poorly differentiated carcinomas consistently expressed diminished CD44s and CD44v6 levels. Lymphocytes and HNSCC lines strongly expressed CD44s but not CD44v6.


CONCLUSIONS
CD44s and CD44v6 expression does not distinguish normal from benign or malignant epithelia of the head and neck. CD44s and CD44v6 were abundantly present in the great majority of cells in head and neck tissues, including carcinomas. Hence, the value of CD44s as a marker for the definition of a small subset of cells (i.e. less than 10%) representing head and neck cancer stem cells may need revision.
Mack
Brigitte
B
Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University of Munich, Munich, Germany.
Gires
Olivier
O
D002294:Carcinoma, Squamous Cell / Q000737:chemistry* / Q000473:pathology; D004848:Epithelium / Q000737:chemistry*; D006257:Head; D006258:Head and Neck Neoplasms / Q000737:chemistry*; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis*; D007150:Immunohistochemistry; D008214:Lymphocytes / Q000737:chemistry*; D009333:Neck; D020033:Protein Isoforms; D014018:Tissue Distribution
C473647:CD44S antigen; C112697:CD44v6 antigen; D018960:Hyaluronan Receptors; D020033:Protein Isoforms