KPT-330, also known as Selinexor, is primarily used in the treatment of certain types of cancer. It is particularly effective in treating multiple myeloma and diffuse large B-cell lymphoma, especially in cases where other treatments have failed. Selinexor works by inhibiting the exportin 1 (XPO1) protein, which is responsible for transporting tumor suppressor proteins out of the cell nucleus. By blocking this process, Selinexor helps to accumulate these tumor suppressor proteins in the nucleus, leading to cancer cell death. This mechanism makes it a valuable option for patients with relapsed or refractory cancers. Additionally, ongoing research is exploring its potential in treating other malignancies, including solid tumors and hematologic cancers. The drug is typically administered orally, making it convenient for outpatient treatment. However, it is often associated with side effects such as nausea, fatigue, and low blood counts, which require careful management. Despite these challenges, Selinexor represents a significant advancement in targeted cancer therapy, offering hope to patients with limited treatment options.