This phase II trial is studying how well suberoylanilide hydroxamic acid works in treating patients with progressive stage IV breast cancer. Drugs used in chemotherapy, such as suberoylanilide hydroxamic acid, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Suberoylanilide hydroxamic acid may also stop the growth of tumor cells by blocking some of the enzymes needed for cell growth