Bortezomib is primarily used in the treatment of multiple myeloma and mantle cell lymphoma. It works by inhibiting the proteasome, a complex that breaks down proteins in cells, leading to the accumulation of damaged proteins and ultimately causing cancer cell death. This mechanism makes it particularly effective in targeting malignant cells.

In clinical practice, it is often administered intravenously or subcutaneously and is commonly used in combination with other chemotherapy drugs or corticosteroids to enhance its efficacy. Its role in managing relapsed or refractory cases of these cancers has been significant, offering improved outcomes for patients. Additionally, ongoing research explores its potential in treating other types of cancers and autoimmune diseases due to its unique mode of action.