CD44 was found as a surface marker in cancer stem cell (CSC) of squamous cell carcinoma of the head and neck (SCCHN); however, the immunologic properties of such CSCs have not yet been elucidated.

The immunologic properties of CD44+ cancer stem‐like cells were compared with those of CD44‐ cells using flow cytometry and enzyme‐linked immunosorbent assay.

CD44+ cells exhibited weak HLA‐A2 and class II expression. Interestingly, downregulation of transporter antigen processing (TAP)2 was found in CD44+ cells. The CD44+ cell population produced significantly higher levels of interleukin (IL)‐8, granulocyte colony‐stimulating factor (G‐CSF), and transforming growth factor (TGF)‐β than the CD44‐ cell population. Moreover, CD44+ cells have been shown to not only more strongly inhibit T‐cell proliferation, but also to more efficiently inhibit regulatory T cells (Treg cells) and myeloid‐derived suppressor cells (MDSC) as compared with CD44‐ cells. Additionally, CD44+ cells suppressed Th1 responses and enhanced regulatory T cell responses.

CSCs might have higher malignant potential with numerous escape strategies from immune attack. © 2010 Wiley Periodicals, Inc. Head Neck, 2011