Construction of an anti-hepatitis B virus preS1 antibody and usefulness of preS1 measurement for chronic hepatitis B patients: Anti-HBV PreS1 antibody.

OBJECTIVES: The preS1 region plays an essential role in hepatitis B virus (HBV) infection. We construct an antibody that binds to preS1 and a measurement system for serum preS1 in chronic HBV-infected patients. METHODS: Hybridoma clones that produce anti-preS1 antibodies were obtained by the iliac lymph node method. Epitope mapping was conducted, and an enzyme-linked immunosorbent assay (ELISA)-based method was developed. Using this ELISA system, serum preS1 levels were measured in 200 chronic HBV-infected patients. RESULTS: Eight types of hybridomas were obtained, of which antibody 3-55 using amino acids 38-47 as the epitope showed high binding affinity to preS1. Serum preS1 levels measured by ELISA using 3-55 antibody were correlated with HBsAg, HBcrAg and HBV DNA levels. Among HBeAg-negative patients without antiviral therapeutic objective (HBV DNA <3.3 log IU/mL or alanine aminotransferase ≤30 U/L), preS1 was significantly higher in subjects who had progressed to the point of requiring antiviral therapy compared to subjects who had maintained their status for the preceding three years (p<0.01). CONCLUSIONS: We constructed an antibody against preS1 and an ELISA system capable of measuring serum preS1 levels. PreS1 may serve as a novel tool to predict the need for antiviral therapy in HBeAg-negative HBV-infected patients.

Tumor Fibroblast Growth Factor Receptor 4 Level Predicts the Efficacy of Lenvatinib in Patients With Advanced Hepatocellular Carcinoma.

OBJECTIVES: Biomarkers for optimizing the outcome of treatment with lenvatinib in patients with advanced hepatocellular carcinoma remain to be established despite intensive and comprehensive genomic research. Lenvatinib is characterized by its prominent inhibitory potency for fibroblast growth factor receptor (FGFR) 4 compared with earlier tyrosine kinase inhibitors. Thus, in this study, we focused on simplified quantification of FGFR4 in tumors as a potential predictive indicator. METHODS: According to The Cancer Genome Atlas data set curation, FGFR4 messenger RNA is broadly overexpressed in hepatocellular carcinoma in the absence of gene alteration. Gene set enrichment analysis revealed that the aggressiveness of the tumor was closely related to the FGFR4 level. To confirm the relationship between the benefits of lenvatinib and tumor addiction to the FGFR4 pathway, we analyzed protein levels in tumors and peripheral blood obtained from 57 prospectively registered patients treated with lenvatinib. RESULTS: Positive immunohistochemistry (>10% of tumor cells) for FGFR4 in biopsy samples before treatment was associated with a longer progression-free survival (2.5 vs 5.5 months, P = 0.01) and a favorable objective response rate (31% vs 81%, P = 0.006). By contrast, the concentration of soluble FGFR4 in peripheral blood as measured by an enzyme-linked immunosorbent assay was not associated with survival outcomes, because its fluctuations reflect hepatic fibrosis. Additional RNA sequencing analysis using archival surgical specimens (n = 90) suggested that alternative RNA splicing of FGFR4 in cancer may also explain this discrepancy. DISCUSSION: The tumor FGFR4 level was an independent predictor of response to lenvatinib.