Investigation of the Potential of Capillary Electrophoresis with Off-Line Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry for Clinical Analysis: Examination of a Glycoprotein Factor Associated with Cancer Cachexia

Abstract

The potential of capillary electrophoresis (CE) with off-line matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry has been demonstrated for the examination of a glycoprotein factor associated with cancer cachexia. A comparison of CE profiles of a healthy volunteer and a cancer patient shows the presence of additional peaks in the electropherogram of the cancer patient that could be associated with cachexia. Micropreparative CE was performed with 180-μm fused silica capillary columns with tapered ends to collect CE fractions for further identification by MALDI-TOF-MS. The analysis of crude urine samples of cancer patients exhibiting cachexia, as well as CE fractions, with MALDI-TOF-MS using ferulic acid as the matrix shows a number of characteristic ions at m/z values of ∼24 and ∼67 kDa. The 24-kDa peak may be identified as the cachectic factor, a glycoprotein, whereas the peak at 67 kDa is identified as albumin, which is present in urine of most patients, and to which the cachectic factor is noncovalently bound. The combined use of CE and MALDI-TOF-MS was successful in detecting cachexia in all of the patients in this study, including one patient that was in an early phase of the disease.