Two-dimensional gel analysis of human endometrial proteins: characterization of proteins with increased expression in hyperplasia and adenocarcinoma

In the search for new markers of human endometrial hyperplasia and adenocarcinoma the method of quantitative two-dimensional gel electrophoresis was applied to study the protein expression profiles of metabolically [S-35]-methionine-labelled proteins of endometrial explants. Approximately 1700 protein spots were resolved by the two-dimensional gel electrophoresis, and the expression pattern of each of these proteins was assessed for increased expression during hyperplasia or adenocarcinoma. In total, six protein spots showed increased expression in hyperplasia, 19 in carcinoma, and eight in both hyperplasia and carcinoma. Twelve of these 33 differentially expressed proteins were identified by peptide mass mapping combined with sequence database searching. Among the identified proteins were proteins involved in cellular transport and chaperoning, i.e. heat shock protein 27 kDa protein, heat shock 70 kDa protein, heat shock cognate 71 kDa protein, and serotransferrin. Other identified proteins were: regulatory chain protein of cAMP-dependent protein kinase, prohibitin, and heterogeneous nuclear ribonucleoprotein A2/B1. Finally we identified proteins associated with the cytoskeleton, vimentin and tropomyosin isoform 3, and the glycolytic pathway, a enolase, and phosphoglycerate kinase. The remaining unidentified proteins were either not contained in the database and must be assumed to be novel proteins, or were present in too low amounts to allow characterization.