ABSTRACT
<p><b>OBJECTIVE</b>To compare the 2-DE profiles for serum proteins of different pathological stages during hepatocarcinogenesis.</p><p><b>METHODS</b>Sera from hepatocellular carcinoma patients, cirrhosis patients, chronic hepatitis patients and healthy controls were collected. After sonication, albumin and immunoglobulin (IgG) depletion, and desalination, sera were subjected to 2-DE, the differential protein spots were identified by MALDI-TOF-MS. Western blot was used to validate these differentially expressed proteins.</p><p><b>RESULTS</b>2-DE sera protein profiles were obtained from the patient suffering from HCC, liver cirrhosis, chronic hepatitis, healthy controls in each group. From optimized 2-DE gel images of the above groups, 96 protein spots with more than 2-fold difference in intensity between the two groups were selected by image master 6.0 software, differential proteins including haptoglobin, SAA1 and SP40 were identified by MALDI-TOF-MS/MS. 7 different spots within more than 30 protein spots belonged to the same haptoglobin family. The differential expression of haptoglobin was confirmed by western blot.</p><p><b>CONCLUSIONS</b>Four protein expression patterns have been identified during the pathological stages of hepatocarcinogenesis. Haptoglobin is significantly increased from liver cirrhosis to HCC. It implies that haptoglobin might be a potential biomarker in the early diagnosis of liver cancer.</p>