<qa>  What is the role of maintenance therapy and timing of administration in MCL?Purpose: This study will evaluate the safety and efficacy of bortezomib and rituximab in patients with relapsed or refractory MCL. Blood, molecular, and tumor analysis will be conducted to provide researchers with information about areas such as rituximab resistance, the effects of bortezomib on cells associated with immune function, and protein alterations related to the cellular growth and death of MCL. In addition, the role of maintenance therapy and timing of administration in MCL will be assessed. 