Background: Primary liver cancer, of which around 75–85% is hepatocellular carcinoma in China, is the fourth most common malignancy and the second leading cause of tumor-related death, thereby posing a significant threat to the life and health of the Chinese people. Summary: Since the publication of Guidelines for Diagnosis and Treatment of Primary Liver Cancer in China in June 2017, which were updated by the National Health Commission in December 2019, additional high-quality evidence has emerged from researchers worldwide regarding the diagnosis, staging, and treatment of liver cancer, that requires the guidelines to be updated again. The new edition (2022 Edition) was written by more than 100 experts in the field of liver cancer in China, which not only reflects the real-world situation in China but also may reshape the nationwide diagnosis and treatment of liver cancer. Key Messages: The new guideline aims to encourage the implementation of evidence-based practice and improve the national average 5-year survival rate for patients with liver cancer, as proposed in the “Health China 2030 Blueprint.”

Objective Hepatocellular carcinoma (HCC) is heterogeneous, especially in multifocal tumours, which decreases the efficacy of clinical treatments. Understanding tumour heterogeneity is critical when developing novel treatment strategies. However, a comprehensive investigation of tumour heterogeneity in HCC is lacking, and the available evidence regarding tumour heterogeneity has not led to improvements in clinical practice. Design We harvested 42 samples from eight HCC patients and evaluated tumour heterogeneity using whole-exome sequencing, RNA sequencing, mass spectrometry-based proteomics and metabolomics, cytometry by time-of-flight, and single-cell analysis. Immunohistochemistry and quantitative polymerase chain reactions were performed to confirm the expression levels of genes. Three independent cohorts were further used to validate the findings. Results Tumour heterogeneity is considerable with regard to the genomes, transcriptomes, proteomes, and metabolomes of lesions and tumours. The immune status of the HCC microenvironment was relatively less heterogenous. Targeting local immunity could be a suitable intervention with balanced precision and practicability. By clustering immune cells in the HCC microenvironment, we identified three distinctive HCC subtypes with immunocompetent, immunodeficient, and immunosuppressive features. We further revealed the specific metabolic features and cytokine/chemokine expression levels of the different subtypes. Determining the expression levels of CD45 and Foxp3 using immunohistochemistry facilitated the correct classification of HCC patients and the prediction of their prognosis. Conclusion There is comprehensive intratumoral and intertumoral heterogeneity in all dimensions of HCC. Based on the results, we propose a novel immunophenotypic classification of HCCs that facilitates prognostic prediction and may support decision making with regard to the choice of therapy.

VISTA (V-domain immunoglobulin suppressor of T cell activation) is a well-established immune regulatory receptor. However, pre-clinical investigations indicated more complicated influences of VISTA on cancer immunity than previously recognized. Here, we review the current knowledge on the therapeutic phenotypes and molecular mechanisms that underlie the contradictory roles of VISTA in checking anti-cancer immune responses. Furthermore, we highlight the potential indeterminacy of VISTA-targeted strategies in cancer immunotherapy, with in silico analyses. In fact, VISTA functions like a homeostatic regulator that actively normalizes immune responses. Thus, the regulatory role of VISTA in anti-cancer immunity remains to be fully elucidated.

Metabolic reprogramming shapes the tumor microenvironment (TME) and may lead to immunotherapy resistance in pancreatic ductal adenocarcinoma (PDAC). Elucidating the impact of pancreatic cancer cell metabolism in the TME is essential to therapeutic interventions. “Immune cold” PDAC is characterized by elevated lactate levels resulting from tumor cell metabolism, abundance of protumor macrophages, and reduced cytotoxic T cells in the TME. Analysis of fluorine-18 fluorodeoxyglucose ( ¹⁸ F-FDG) uptake in patients showed that increased global protein lactylation in PDAC correlates with worse clinical outcomes in immunotherapy. Inhibition of lactate production in pancreatic tumors via glycolysis or mutant-KRAS inhibition reshaped the TME, thereby increasing their sensitivity to immune checkpoint blockade (ICB) therapy. In pancreatic tumor cells, lactate induces K63 lactylation of endosulfine α (ENSA-K63la), a crucial step that triggers STAT3/CCL2 signaling. Consequently, elevated CCL2 secreted by tumor cells facilitates tumor-associated macrophage (TAM) recruitment to the TME. High levels of lactate also drive transcriptional reprogramming in TAMs via ENSA-STAT3 signaling, promoting an immunosuppressive environment. Targeting ENSA-K63la or CCL2 enhances the efficacy of ICB therapy in murine and humanized pancreatic tumor models. In conclusion, elevated lactylation reshapes the TME and promotes immunotherapy resistance in PDAC. A therapeutic approach targeting ENSA-K63la or CCL2 has shown promise in sensitizing pancreatic cancer immunotherapy.

PD-1 (CD279)–PD-L1 (CD274) inhibitory signaling is critical for cancer immune evasion, and thus has become one of the major targets in anticancer immunotherapy. There are several studies that demonstrate the potent effects of posttranslational modifications of CD274 on immune inactivation and suppression, such as ubiquitination, phosphorylation, glycosylation, and palmitoylation. However, the regulatory mechanisms for CD274 deubiquitination are still largely unclear. Here, we identified ubiquitin-specific protease 22 (USP22) as a novel deubiquitinase of CD274. USP22 directly interacted with the C terminus of CD274, inducing its deubiquitination and stabilization. Across multiple cancer types, USP22 was highly expressed and frequently altered in liver cancer, closely correlating with poor prognosis of these patients. Genetic depletion of USP22 inhibited liver cancer growth in an immune system–dependent manner, increased tumor immunogenicity and tumor-infiltrating lymphocytes, and improved therapeutic efficacy of CD274-targeted immunotherapy and CDDP-based chemotherapy in mice. We demonstrate that targeting USP22 is a promising strategy to potentiate anticancer immunity for CD274-amplified cancer.