Disclosed herein are methods for treating a cancer and a method for sensitizing a cancer to a chemotherapeutic agent. Each method administers an agent that selectively inhibits HDAC1 and HDAC2 to a subject in need thereof. Also disclosed herein are methods for determining if a cancer is sensitive to an agent that selectively inhibits HDAC1 and HDAC2 and methods for monitoring the efficacy of a treatment for a cancer that includes administration of an agent that selectively inhibits HDAC1 and HDAC2.