Carcinoma, Squamous Cell/metabolism; DNA-Binding Proteins/genetics; Head and Neck Neoplasms/metabolism; Membrane Proteins; Neoplasm Recurrence, Local/metabolism; Nuclear Proteins/genetics; Phosphoproteins/genetics; Trans-Activators/genetics; Tumor Suppressor Protein p53/genetics; Carcinoma, Squamous Cell/genetics; Carcinoma, Squamous Cell/pathology; DNA Mutational Analysis; DNA Primers/chemistry; DNA, Neoplasm/analysis; DNA-Binding Proteins/metabolism; Gene Expression; Genes, Tumor Suppressor; Head and Neck Neoplasms/genetics; Head and Neck Neoplasms/pathology; Humans; Immunoenzyme Techniques; Neoplasm Recurrence, Local/genetics; Neoplasm Recurrence, Local/pathology; Neoplasm Staging; Nuclear Proteins/metabolism; Phosphoproteins/metabolism; RNA, Messenger/metabolism; RNA, Neoplasm/genetics; Reverse Transcriptase Polymerase Chain Reaction; Trans-Activators/metabolism; Transcription Factors; Tumor Protein p73; Tumor Suppressor Protein p53/metabolism; Tumor Suppressor Proteins