Stanniocalcin 1 is a serum biomarker and potential therapeutic target for HBV-associated liver fibrosis

Stanniocalcin 1 (STC1), a secreted protein, is upregulated in human cancers including hepatocellular carcinoma (HCC). While most HCCs develop from chronic liver disease, which involves progressive parenchymal injury and fibrosis, the role of STC1 in this preneoplastic stage remains poorly understood. In this study we investigated the clinical relevance and functional significance of secreted STC1 in liver fibrosis. To this end, the STC1 level was determined in the serum samples of chronic hepatitis B patients and correlated with the degree of liver fibrosis. Diagnostic performance of STC1 was analysed by area under the receiver operating characteristic curve (AUROC), sensitivity, specificity, positive predictive value, and negative predictive value. The results were compared with other well-characterised serum biomarkers for liver fibrosis: Aspartate transaminase to Platelet Ratio Index (APRI) and Fibrosis-4 (FIB-4). The functional role of STC1 was interrogated by in vitro experiments using cell line models. Expression of fibrogenic markers was quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. Our results showed that the serum STC1 level in chronic hepatitis B patients was positively correlated with the degree of liver fibrosis and showed a stepwise increase in accordance with the severity of fibrosis. The AUROCs for detecting significant fibrosis (>9.0 kPa) and cirrhosis (>12.0 kPa) was 0.911 and 0.880, respectively. STC1 demonstrated a superior specificity and positive predictive value when compared to APRI and FIB-4. Consistent with this, STC1 was elevated in the liver tissues and sera of CCl₄ -treated mice showing marked liver fibrosis. In vitro, STC1 was secreted by the human hepatic stellate cell line LX2. Human recombinant STC1 (rhSTC1) induced expression of fibrogenic markers in LX2 cells. The profibrogenic phenotype conferred by rhSTC1 or TGF-β1 in LX2 cells could be attenuated using anti-STC1 antibody. Taken together, STC1 is a specific serum biomarker for HBV-associated liver fibrosis. STC1 functionally promotes liver fibrogenesis and is a potential actionable target. © 2022 The Pathological Society of Great Britain and Ireland.