Carcinoma, Squamous Cell/metabolism; Catalytic Domain/physiology; Head and Neck Neoplasms/metabolism; Lung Neoplasms/metabolism; Phosphoinositide-3 Kinase Inhibitors; Protein Serine-Threonine Kinases; Tumor Suppressor Protein p53/metabolism; Apoptosis; Carcinoma, Squamous Cell/pathology; Cell Survival/drug effects; Cell Survival/physiology; DNA Mutational Analysis; Down-Regulation; Gene Expression Regulation, Neoplastic/physiology; Head and Neck Neoplasms/pathology; Humans; PTEN Phosphohydrolase; Phosphatidylinositol 3-Kinases/genetics; Phosphatidylinositol 3-Kinases/metabolism; Phosphoric Monoester Hydrolases/deficiency; Phosphoric Monoester Hydrolases/genetics; Phosphoric Monoester Hydrolases/metabolism; Protein Subunits; Proto-Oncogene Proteins/metabolism; Proto-Oncogene Proteins c-akt; Signal Transduction/drug effects; Signal Transduction/physiology; Tumor Cells, Cultured; Tumor Suppressor Protein p53/pharmacology; Tumor Suppressor Proteins/deficiency; Tumor Suppressor Proteins/genetics; Tumor Suppressor Proteins/metabolism