We previously found a statistically significant number of cytokeratin 19 (CK19)+ cells in peripheral blood (PB) of stage IV breast cancer (BC) patients compared with those of healthy volunteers, using a quantitative real-time reverse transcription-PCR.
In this pilot study, we detected significantly elevated CK19 transcript levels in < 10% of the volunteers, in +/- 30% of stage I-IIIa patients preoperatively and in > 70% of the and stage IV breast cancer patients.