Identification and evaluation of fructose-bisphosphate aldolase B as a potential diagnostic biomarker in choledochal cysts patients: a quantitative proteomic analysis

BACKGROUND: Choledochal cyst (CC) is a congenital bile duct malformation, with a higher incidence in minors. Patients with CCs are at risk of pancreatitis and ascending cholangitis. The main forms of treatments aim to avoid any possible hepatic, pancreatic, or biliary complications. Since early diagnosis is of great importance for CC treatment and prognosis, this investigation was designed to screen and identify potential biomarkers from the serum samples of CC patients for CC early diagnosis. METHODS: Quantitative label free proteomic analysis was used to identify differentially expressed proteins in serum samples from CC patients and normal healthy children. The expression levels of biomarker candidates were further confirmed using quantitative polymerase chain reaction (Q-PCR), Western blot analysis, and immunohistochemistry in the choledochal tissues. RESULTS: The quantitative label free proteomic analysis identified 47 differentially expressed proteins in the serum samples from the CC patients and the normal children, including 14 up-regulated proteins and 33 down-regulated proteins. The expression profile of eight biomarker candidates in CC patients, namely, insulin-like growth factor binding protein 2 (IGFBP2), tropomyosin (TPM3), fructose-bisphosphate aldolase B (ALDOB), fumarylacetoacetate hydrolase (FAH), superoxide dismutase 3 (SOD3), secreted protein acidic and cysteine rich (SPARC), apolipoprotein E (APOE), and retinol binding protein 4 (RBP4), were selected for further examination in choledochal tissues, showing that ALDOB was significantly increased. CONCLUSIONS: The results demonstrated that the ALDOB protein increased significantly in choledochal tissues and the serum samples of CC patients, which may serve as an effective predictor for early diagnosis of CC.