SIRT1 and head and neck squamous cell carcinoma: Albeit not statistically significant, a negative correlation between SIRT1 expression and OS was also observed in esophageal squamous cell carcinoma, kidney renal papillary cell carcinoma, lung squamous cell carcinoma, sarcoma, and uterine corpus endometrial carcinoma patients; a negative association between SIRT1 expression and RFS was also noted in cervical squamous cell carcinoma, esophageal squamous cell carcinoma, head-neck squamous cell carcinoma, kidney renal papillary cell carcinoma, pancreatic ductal adenocarcinoma, and stomach adenocarcinoma patients (Figure S2A,B).