CTC identification.

<p>For CTC enumeration, EpCAM-positive cells were first isolated from patient blood samples, after which they were immunofluorescently identified. DAPI (blue) was used to stain the cell nucleus. Alexa-647-labeled anti-CD45 antibodies (red) were used to stain the leukocyte marker CD45. FITC-labeled anti-CK19 antibodies (green) were used to stain CK19, which is widely accepted as a marker of breast cancer CTCs. Therefore, CTCs (A) exhibited a status of DAPI+/CD45-/CK19+, which were colored blue and green, but not red. Typical leukocytes (B) were DAPI+/CD45+/CK19- and colored blue and red, but not green. Scale bar: 5 μm.