The detection of circulating breast cancer cells in peripheral blood by reverse transcriptase-polymearse chain reaction

Some circulating cancer cells in the blood play a central role in the metas tatic process and may have a major influence on patient progress. Their num bers can be very small and techniques for their detection need to be both s ensitive and specific. Polymerase chain reaction (PCR) has been successfull y used to detect small numbers of tumor cells in cancer. We used a reverse transcriptase-polymerase chain reaction (RT-PCR) to detect circulating brea st cancer cells in venous blood samples before operations and assessed cyto keratin-19 (CK-19) and cytokeratin-20 (CK-20) as target mRNA markers in the blood of healthy donors (n=6) and breast cancer patients (n=30) with Ameri can Joint Committee on Cancer stages 0 to IIa. CK-19 mRNA was expressed in all blood samples of healthy donors and patients. But CK-20 was the only mR NA marker not detected in the blood from healthy donors. Seven of 30 (23%) venous blood isolates of breast cancer patients yielded a CK-20 mRNA with p ositive results. There was no correlating CK-20 mRNA expression with stage and axillary lymph node status. In conclusion, CK-19 showed no diagnostic v alue as a mRNA marker in the detection of circulating cancer cells by RT-PC R assay because this was expressed in the blood of healthy donors. CK-20 mR NA was an useful marker to detect circulating cancer cells in breast cancer s.