Different role of circulating myeloid-derived suppressor cells in patients with multiple myeloma undergoing autologous stem cell transplantation ================================================================================================================================================ * Sung-Eun Lee * Ji-Young Lim * Tae Woo Kim * Da-Bin Ryu * Sung Soo Park * Young-Woo Jeon * Jae-Ho Yoon * Byung-Sik Cho * Ki-Seong Eom * Yoo-Jin Kim * Hee-Je Kim * Seok Lee * Seok-Goo Cho * Dong-Wook Kim * Jong Wook Lee * Chang-Ki Min