Patients assigned to VGPR, PR, and SD in the IMWG response category are composed of heterogeneous population when assessed by the heavy/light chain assay. Issue 3 (26th April 2019) - Kamiya, Yoshikazu; Chou, Takaaki; Murakami, Hirokazu; Handa, Hiroshi; Ozaki, Shuji; Shimazaki, Chihiro; Fuchida, Shin‐ichi; Okada, Jun; Itoh, Junji; Sugiyama, Satoru; Shimizu, Kazuyuki