 The purpose of this study is to monitor such factors as a past history, a previous history of drug use, the degree of response to initial treatment, the frequency of previous therapies, age, Eastern Cooperative Oncology Group ECOG performance status, which is used by doctors and researchers to assess how a patients disease is progressing, assess how the disease affects the daily living abilities of the patient, and determine appropriate treatment and prognosis, before the bortezomib re-treatment, the concomitant drugs that are used for re-treatment and the pattern of treatment in patients with multiple myeloma who were re-treated with injectable bortezomib. 