Serial quantitative PCR analysis of bone marrow samples from breast cancerpatients to monitor systemic micrometastases

Background: We have previously developed a quantitative calibrated PCR assa y to measure cytokeratin 19 (CK19) expression in haematopoietic tissue in o rder to detect systemic micrometastases. Patients and Methods: Serial measu rements of CK19 expression in bone marrow of patients with primary breast c ancer were performed at operation, at 3 week,; and 6 months postoperatively . Results: Reference values for CK19 expression were established by analysi ng bone marrow samples from 48 healthy female volunteers or patients withou t epithelial cancer. Samples from breast cancer patients with CK19 values a bove the upper reference limit were considered positive, Bone marrow sample s taken at operation were positive in 29 out of 141 patients (20.6%) and re mained positive in 12, turned negative in 4 and were unavailable in 13 at 6 months postoperatively. Conclusion: Serial measurements increase the relia bility of detecting micrometastases perioperatively. Further studies are in progress to evaluate the relationship between elevated CK 19 values and cl inical outcome.