1. Department of Pathology, Second People's Hospital of Neijiang, Neijiang, 641100 Sichuan, PR China
2. Department of Gynecology, First People's Hospital of Yunnan Province, Kunming, 650032 Yunnan, PR China
3. Department of Pathology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000 Sichuan, PR China
4. Department of Human Anatomy, Southwest Medical University, Luzhou, 646000 Sichuan, PR China