We evaluated the differentially expressed proteins in the plasma of ovarian cancer (OVC) patients using2-D SDS-polyacrylamide gel electrophoresis (SDS-PAGE) with post-translational modification (PTM)specific stains after the removal of six high-abundance proteins. The pooled plasma from patients withstage III or IV OVC was compared to a pooled postmenopausal age-matched control. Several proteinswere identified as differentially expressed in the plasma of OVC patients. Among them, the phosphorylated fibrinogen-
-chain isoform (containing fibrinopeptide-A) was found to be up-regulated.Previously in our laboratory, phosphorylated fibrinopeptide-A was found to be up-regulated in the lowmolecular weight fraction of serum derived from OVC patients. We examined the levels of phosphorylated fibrinogen-
-chain in each patient that constituted the pooled plasma using Western blot,mass spectrometry (MS), and PTM specific stains. Phosphoprotein bands containing fibrinogen-
-chainfragments showed up-regulation in all OVC patients.