The introduction of a proteasome inhibitor bortezomib has significantly improved response rates and overall survival in patients with multiple myeloma (MM), and it has soon become the cornerstone of treatment in both newly diagnosed and relapsed/refractory settings. However, the incidence of peripheral neuropathy related to bortezomib (BiPN) is unignorable and which becomes an obstacle during treatment with bortezomib, either alone or in combination. Until now, there are no consistent findings regarding the risk factors that may cause BiPN. There is either lack of large scale study of BiPN in Taiwan. This study aims to clarify risk factors of BiPN using retrospective analysis in a large cohort with longer observation period as well as the relations between BiPN and gene polymorphisms, and to compare different routes in the incidence of BiPN.