CS and head and neck squamous cell carcinoma: Interestingly, compared with corresponding healthy tissues, the CS expression level is significantly increased within the ECM of many human solid tumors25, such as hepatocellular carcinoma (HCC) and head and neck squamous cell carcinoma (HNSCC)26, 27, 28, which indicates that CS is closely related to tumor occurrence, progression and metastasis12, 29.