Refractory Alveolar Soft Part Sarcoma

This phase II trial tests whether atezolizumab in combination with selinexor works to shrink tumors in patients with alveolar soft part sarcoma and whether the study drugs are better than the usual approach in treating this type of cancer. The usual approach is defined as care most people get for alveolar soft part sarcoma if they are not part of a clinical study, which includes treatment with radiation, kinase inhibitor drugs, immunotherapy drugs, or chemotherapy drugs. Immunotherapy with monoclonal antibodies, such as atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Selinexor is in a class of medications called selective inhibitors of nuclear export (SINE). It works by blocking a protein called CRM1, which may help keep cancer cells from growing and may kill them. Giving atezolizumab in combination with selinexor may help shrink tumors and stabilize the cancer in patients with alveolar soft part sarcoma.