1 Division of Hematology-Oncology, Department of Internal Medicine, Korea University College of Medicine, 73, Goryeodae-ro, Seongbuk-gu, Seoul, 02841, South Korea.
2 Department of Biostatistics, Korea University College of Medicine, Seoul, South Korea.
3 Division of Hematology-Oncology, Department of Internal Medicine, Korea University College of Medicine, 73, Goryeodae-ro, Seongbuk-gu, Seoul, 02841, South Korea. paark76@hanmail.net.