Summary table of meta-analysis.

Study design is described as consecutive patients (C), prospective (P) or retrospective (R). –, not reported; HNSCC, head and neck squamous cell carcinomas; PDAC, pancreatic ductal adenocarcinoma; qRT-PCR, quantitative real-time PCR; OS, overall survival; DSS, disease-specific survival; DFS, disease-free survival; RFS, relapse-free survival; PFS, Progression-free survival; AP, author provided; DE, data-extrapolated; SC, survival curve.*the OS data is obviously not consistent with the survival curves, so only provided DFS is used for analysis.