研究目的:
                        
                            Head and neck Squamous Cell Carcinoma (HNSCC) is one of the most common head and neck        malignant tumors .Investigators found that several patients with early TNM stage and poor        differentiated HNSCC had poor prognosis, yet someone with advanced TNM stage and well        differentiated HNSCC had good prognosis. Hence, Investigators suggested that prognosis        factors and survival rates probably related to the differentiation of HNSCC, and prognosis        factor of poorly differentiated HNSCC were rare discussed and controversy. Investigating the        prognostic factors of poorly differentiated HNSCC is undoubtedly crucial.