CD44 and head and neck squamous cell carcinoma: Among them, the high expression of CD200 is related to the immune escape and poor prognosis of malignant tumors (Jung et al. 2015; Shin et al. 2019), and the regulatory role of CD44 in cancer stem cells of HNSCC patients has been clarified in recent researches (Liu et al. 2023; Sharaf et al. 2021).