Dr. Howard Scher, MD, is Chief, Genitourinary Oncology Service, Sidney Kimmel Center for Prostate and Urologic Cancers, Memorial Sloan-Kettering Cancer Center. Prostate cancer is a heterogeneous disease for which reliable measures to guide decisions regarding therapy and to monitor treatment effect are needed. Here, Dr. Howard Scher discusses the current use of circulating tumors cells (CTCs) in clinical practice and context for their development for other applications.How does analysis of circulating...