Plasma levels of HER-2/neu, tumor type M2 pyruvate kinase and its tyrosine-phosphorylated metabolite in advanced breast cancer.

Introduction: Tyrosine kinase signal transduction pathways are a focus of interest for therapeutic interventions. The oncoprotein HER-2/neu shows tyrosine kinase activity leading to phosphorylation and activation of numerous second-messenger systems. One target of phosphorylation processes is assumed to be the tumor type M2 isoenzyme of pyruvate kinase (TuM2-PK) which has been shown to be elevated in metastatic breast cancer.

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 been demonstrated in solid tumors. We investigated this marker in 67 patients with advanced breast cancer (ABC) in comparison to healthy controls.

Materials And Methods: Plasma Tu M2-PK was measured using an ELISA assay (ScheBo Tech, Giessen, Germany) while serum CA27.