Circulating cancer cells (CCC) in breast cancer (BC) patients

504 Background: Numbers and characterization of CCC may provide information relevant to prognosis and treatment of cancer patients (Pts.). We conducted a blood sampling study in pts. with histologically confirmed BC to assess for presence of CCC. Methods: Approximately 15 ml of venous blood were collected (before systemic therapy and periodically thereafter) and processed with a negative selection procedure using double-gradient centrifugation and magnetic cell sorting to remove RBC and WBC. The cells were stained with anti-pancytokeratin-FITC cocktail and DAPI (DNA stain). Digital images of FITC-positive cells were acquired with a fluorescence microscope for enumeration of CCC. Cells from 21 pts. were also stained simultaneously with labeled Trastuzumab antibody to quantify the HER-2/neu expression relative to a fluorescence standard. Results: 74 pts were accrued and 203 blood samples were drawn; median number of samples drawn per patient was 3 (1–5). Patient characteristics: median age 52 (32–84), race ...