Previously, associations of combined 18F-FDG-PET and MRI parameters with histopathological features depended on tumor grading and correlated strongly with tumor cell expression of Ki-67 and HIF-1α in head and neck squamous cell carcinoma (HNSCC).120 Also, this metabolic imaging biomarker-based parameters are useful for evaluation of prognostic significance. This evidence concerns the gene HIF1A and neoplasm.