Liver stiffness measurement predicts short-term and long-term outcomes in patients with hepatocellular carcinoma after curative liver resection.

BACKGROUND AND AIM: Hepatocellular carcinoma is one of the commonest cancer in the world. Despite curative resection, recurrence remains the largest challenge. Many risk factors were identified for predicting recurrence, including liver fibrosis and cirrhosis. Transient elastography (Fibroscan) is an accurate tool in measuring liver fibrosis. This study aimed to evaluate the use of preoperative liver stiffness measurement (LSM), with Fibroscan in predicting long-term recurrence of hepatocellular carcinoma (HCC) after curative resection. METHOD: A prospective cohort study was conducted from February 2010 - June 2017 in Prince of Wales hospital. All consecutive patients with HCC undergone hepatectomy were included. Demographic factors, preoperative LSM, tumor characteristics and operative details were assessed. Primary outcome and secondary outcome were overall survival and disease free survival at 1 year, 3 year and 5 year respectively. RESULTS: A total of 401 cases were included. Patients with LSM ≥12kPa had significantly lower 5-year overall survival rate (75.1% vs 57.3%, p < 0.001) and disease free survival rate (45.8% vs. 26.7%, p < 0.001). On multivariate analysis, pre-operative creatinine and vascular invasion of tumor were significant factors in predicting early recurrence (p = 0.012 and p = 0.004). LSM ≥12kPa were the only significant factor in predicting late recurrence (p = 0.048). CONCLUSION: Pre-operative liver stiffness measurement could predict the late recurrence of hepatocellular carcinoma after curative resection.

PPP1R15A-expressing monocytic MDSCs promote immunosuppressive liver microenvironment in fibrosis-associated hepatocellular carcinoma.

Background & Aims: Recent studies demonstrated the importance of fibrosis in promoting an immunosuppressive liver microenvironment and thereby aggressive hepatocellular carcinoma (HCC) growth and resistance to immune checkpoint blockade (ICB), particularly via monocyte-to-monocytic myeloid-derived suppressor cell (M-MDSC) differentiation triggered by hepatic stellate cells (HSCs). We thus aimed to identify druggable targets in these immunosuppressive myeloid cells for HCC therapy. Methods: M-MDSC signature genes were identified by integrated transcriptomic analysis of a human HSC-monocyte culture system and tumor-surrounding fibrotic livers of patients with HCC. Mechanistic and functional studies were conducted using in vitro-generated and patient-derived M-MDSCs. The therapeutic efficacy of a M-MDSC targeting approach was determined in fibrosis-associated HCC mouse models. Results: We uncovered over-expression of protein phosphatase 1 regulatory subunit 15A (PPP1R15A), a myeloid cell-enriched endoplasmic reticulum stress modulator, in human M-MDSCs that correlated with poor prognosis and ICB non-responsiveness in patients with HCC. Blocking TGF-ß signaling reduced PPP1R15A expression in HSC-induced M-MDSCs, whereas treatment of monocytes by TGF-ß upregulated PPP1R15A, which in turn promoted ARG1 and S100A8/9 expression in M-MDSCs and reduced T-cell proliferation. Consistently, lentiviral-mediated knockdown of Ppp1r15a in vivo significantly reduced ARG1+S100A8/9+ M-MDSCs in fibrotic liver, leading to elevated intratumoral IFN-γ+GZMB+CD8+ T cells and enhanced anti-tumor efficacy of ICB. Notably, pharmacological inhibition of PPP1R15A by Sephin1 reduced the immunosuppressive potential but increased the maturation status of fibrotic HCC patient-derived M-MDSCs. Conclusions: PPP1R15A+ M-MDSC cells are involved in immunosuppression in HCC development and represent a novel potential target for therapies. Impact and implications: Our cross-species analysis has identified PPP1R15A as a therapeutic target governing the anti-T-cell activities of fibrosis-associated M-MDSCs (monocytic myeloid-derived suppressor cells). The results from the preclinical models show that specific inhibition of PPP1R15A can break the immunosuppressive barrier to restrict hepatocellular carcinoma growth and enhance the efficacy of immune checkpoint blockade. PPP1R15A may also function as a prognostic and/or predictive biomarker in patients with hepatocellular carcinoma.