1. Department of Pathology, Shandong University School of Medicine, Jinan 250012, China
2. Department of Gastroenterology, Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
3. Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
4. Department of Oncology-Pathology, Karolinska Institutet, CCK Karolinska University Hospital, Stockholm SE-171 76, Sweden