The Clinical Significance of Circulating Tumor Cells in the Peripheral BloodElshimali, Yahya I. MD*; Grody, Wayne W. MD, PhD†Diagnostic Molecular Pathology: December 2006 - Volume 15 - Issue 4 - pp 187-194 doi: 10.1097/01.pdm.0000213463.98763.b9 Review Article Buy Abstract Author Information Tumors launch malignant cells into the circulation continuously. In early stages, the immune surveillance system eliminates these cells from the circulation, but at later times they may persist longer and be detected. The first recorded evidence of the presence of circulating tumor cells in the peripheral blood of cancer patients was documented in 1869. Now, modern molecular biologic and cell sorting techniques make their detection and characterization more practicable. This review will consider the methods currently available for their detection and characterization, and the clinical implications of their presence in various malignant conditions. *Department of Pathology and Laboratory Medicine, Olive View-UCLA Medical Center, Sylmar †Department of Pathology and Laboratory Medicine, UCLA Medical Center, Los Angeles, CA Reprints: Yahya I. Elshimali, MD, Department of Pathology, 14445 Olive View Drive, Sylmar, CA 91342 (e-mail: Yelshimali@ladhs.org). © 2006 Lippincott Williams & Wilkins, Inc.