In HNSCC, Prince et al. first demonstrated that a CD44+ population of cells possesses the properties of CSC [9], but relatively high numbers of these cells (>5,000 cells) were needed to generate new tumors in immunodeficient mice indicating either a low frequency of CSC or a low specificity of CD44 as CSC-marker in HNSCC. This evidence concerns the gene CD44 and head and neck squamous cell carcinoma.