A substance being studied in the treatment of cancer. Belinostat blocks enzymes needed for cell division and may kill cancer cells. It also prevents the growth of blood vessels needed for tumors to grow and may make tumor cells more sensitive to other anticancer drugs. It is a type of histone deacetylase (HDAC) inhibitor, a type of angiogenesis inhibitor, and a type of chemosensitizer. Also called PXD101.