This document provides methods and materials for treating cancer. For example, methods and materials for identifying a mammal as having cancer cells that express little, or no, Parkin mRNA or Parkin polypeptide and administering one or more mitotic kinase inhibitors to treat the mammal identified as having cancer cells with a Parkin deficiency are provided. Methods and materials for identifying a mammal as having a cancer that is responsive to treatment with one or more mitotic kinase inhibitors also are provided.
