RAD21 and head and neck squamous cell carcinoma: The top 5 CDCAs neighboring gene alterations in HNSCCs were found in MYC, STAG1, RAD21, KLHL9 and NDC80. Multivariable Cox proportional hazard model also showed that CD8+ T cells were higher (P<0.05) in HNSCC-HPV-pos patients and that this was related to CDCA1/2/3/4/5/7.