1. Department of Pathology, Weifang Medical University, Weifang, Shandong, P.R. China
2. Department of Pathology,
Affiliated hospital, Weifang Medical University, Weifang, Shandong, PR China
3. Department of Histology and Embryology,
Weifang Medical University, Weifang, Shandong, P.R. China