OBJECTIVETo prepare antibodies (pAbs) against phosphorylated Y-box binding protein 1 (pYB-1), perform qualitative detection of the ascites/pYB-1 ratio in patients with hepatocellular carcinoma with pulmonary metastasis (HCC-PM), and assess the clinical significance of the ascites/pYB-1 ratio as a diagnostic biomarker for HCC-PM.

METHODSBioinformatic prediction and chemical synthesis was used to identify and generate the YB-1 polypeptide with phosphorylation at serine position 102 (KYLRSVGDG). Rabbits were immunized with the YB-1 polypeptide coupled to a carrier protein. Protein A affinity chromatography was used to prepare highly-purified pAbs.ELISA and SDS-PAGE were used to determine concentration and purity of the pAbs. A total of 109 ascites specimens were collected from patients (36 cases of HCC,44 cases HCC-PM, and 29 cases of liver cirrhosis) and concentrated to obtain the pYB-1. Western blotting was used to qualitatively detect pYB-1 in ascites. Regression analysis and receiver operating characteristic (ROC) curve analysis were used to assess the qualitative data.

RESULTSThe prepared pAbs had a concentration of more than or equal to 1:1 * 106 and high purity. The pAbs/YB-1S102 specifically recognized endogenous pYB-1S102. The pYB-1S102 detected in ascites specimens from patients with HCC and HCC-PM, and the positive rate of detection was 30.6% and 77.3% respectively (P < 0.01).The pYB-1S102 showed sensitivity of 77.3% and a accuracy rate of 73.8% for diagnosis of HCC-PM.

CONCLUSIONDetection of pYB-1S102 in ascites could be a useful biomarker for diagnosis and metastasis monitoring in patients with HCC.