Methods are provided for treating cancer and other dysproliferative diseases by administering to a subject in need there of a therapeutically effective amount of a synergistic composition comprising an HER2 inhibitor, or a pharmaceutically acceptable salt or prodrug thereof and a CYP26 inhibitor, or a pharmaceutically acceptable salt or prodrug thereof wherein said therapeutically effective amount suppresses the growth of dysproliferative cells in vivo. Compositions comprising a combination of an HER2 inhibitor, or a pharmaceutically acceptable salt or prodrug thereof and a CYP26 inhibitor a pharmaceutically acceptable salt or prodrug thereof are also described.
