L L Xuan1, J G Wei2, H G Liu3. 1. Department of Pathology, Anqing Hospital,Anhui Medical University,Anqing Municipal Hospital,Anqing 246003,China. 2. Department of Pathology, Shaoxing People's Hospital, Shaoxing 312000, China. 3. Department of Pathology, Beijing Tongren Hospital, Capital Medical University, Beijing Key Laboratory of Head and Neck Molecular Diagnostic Pathology, Beijing 100730, China.