CD44 and head and neck squamous cell carcinoma: Similarly, Zhang et al.11 reported that CD44 was related to cellular states and phenotypes of tumor cells in breast cancer, while Gomez et al.12 noted that CD44 expression influenced cancer cell plasticity through tumor-associated macrophages (TAM), inferring that CD44 is a surface marker defining Head and neck squamous cell carcinoma (HNSC).