Serum albumin-associated peptides of patients with uterine endometrial cancer.

The incidence of endometrial cancer is predicted to increase in developed countries. Because of the relatively high incidence of complications and low diagnostic sensitivity associated with endometrial tissue sampling, there is an urgent need for the development of a safe and non-invasive diagnostic method. The proteomic spectrum of albumin-associated peptides was obtained from a total of 125 serum samples (92 from endometrial cancer patients and 33 from controls) by matrix-assisted laser desorption/ionization hybrid quadrupole time-of-flight mass spectrometry, and the candidate markers were selected by the Mann-Whitney U-test and receiver operator characteristics analysis. We selected three mass peaks at 4769, 6254 and 11 792 m/z from a total of 507 peaks as distinguishing cancer patients from controls (P < 0.00001 and area under curve of over 0.8). When the cut-off points were defined as the averages of the values in the controls + 2 SD, the combination of the three peptides detected endometrial cancer with a sensitivity of 65.2% (60/92). Even stage I early endometrial cancers were detected with a sensitivity of 60.3% (38/63). Unfortunately, the three peptides were also detected in 44.6% (33/74) of myoma uteri patients, indicating that they are not specific to endometrial cancer. Although a large-scale study is necessary to confirm the clinical significance of the peptide biomarkers identified in this study, direct profiling of serum-albumin-bound peptides by high-resolution mass spectrometry was proven to have potential as a means of identifying biomarkers for a variety of diseases.