Tumor type M2 pyruvate kinase expression in advanced breast cancer

Background: Recently, a high validity correlation of the tumor M2 pyruvate kinase (Tu M2-PK) isoenzyme in comparison to standard tumor markers has bee n demonstrated in solid tumors. We investigated this markers in 67 patients with advanced breast cancer (ABC) in comparison to healthy controls. Mater ials and Methods: Plasma Tu M2-PK was measured using an ELISA assay (ScheBo (R) Tech Giessen, Germany) while serum CA27.29 was determined using a chemi luminescent immunoassay (Bayer Diagnostics Tarrytown, USA). Results: In a R OC analysis, the art-off to discriminate patients from controls was establi shed at 15 U/ml for Tu M2-PK (specificity 85%; positive predictive value 81 %) and 30 U/ml for CA27.29 (specificity 91%; positive predictive value 92%) . Median ABC baseline levels (ranges) in patients with ABC Sol Ttl M2-PK an d CA27.29 were 12.8 U/ml (4.8-252495) and 130 U/ml (13.3-8130), respectivel y. Response assessment was done in 45 chemotherapy courses of 35 pts. In 13 out of 19 blocks (68.4%) with PD (progressive disease), an elevated level of Tu M2-PK at baseline ol in the follow-lip was found In 17 out of 20 bloc k (85%) with SD (stable disease), the Tn M2-PK level was normal at baseline ol normalised within 4 week of treatment. All 6 patients with disease remi ssion had a normal baseline Tn M2-PK level or the levels decreased promptly . Conclusion: Tu M2-PK gives additional information about ABC, indicating d isease activity and sensitivity to chemotherapy while CA27.29 reflects tumo r burden.