Hepatocellular carcinoma (HCC) is the most frequently diagnosed primary liver cancer with a high mortality rate and imposes a huge burden on patients and society. Recently, ubiquitin‑specific protease 35 (USP35) was found to be involved in cell proliferation and mitosis, but its role in HCC remains largely unknown. The expression of USP35 in HCC and its association with patient prognosis in the study cohort and public databases was analyzed in the present study. The effects of USP35 on the malignant biological behavior of HCC were analyzed by cellular functional experiments. Mechanistically, the effect of USP35 deubiquitylation on the M2 splice isoform of pyruvate kinase (PKM2) and on the Warburg effect of tumor cells were verified by western blotting and ubiquitination assay. The results of the present study demonstrated that USP35 is highly expressed in HCC and its high expression is significantly associated with poor prognosis of patients with HCC. In the present study, it was also demonstrated that inhibiting the expression of USP35 can impair the malignant properties (proliferation, migration and invasion) of HCC tumor cells by elevating the ubiquitination level of PKM2, the deubiquitinated form of which is critical for glycolysis in tumor cells. The present study therefore indicated that USP35 may be a target in the treatment of HCC.

INTRODUCTION: Carbohydrate antigen 19-9 (CA19-9) and α-fetoprotein (AFP) are routinely tested in patients with liver malignancies before surgery. However, few reports have explored the relevance of the expression pattern of these 2 tumor markers regarding the prognosis of intrahepatic cholangiocarcinoma (ICC). We herein combined these 2 tumor markers to investigate the influence on ICC malignancy and patient prognosis. METHODS: From March 2009 to December 2019, 519 consecutive patients with newly diagnosed ICC who underwent R0 resection were enrolled and followed. The relationships between clinicopathological parameters and these 2 tumor markers were analyzed. Propensity score matching was used to eliminate the baseline differences. RESULTS: A lower proportion of patients with double-negative AFP and CA19-9 had advanced tumor-node-metastasis stage, larger tumor diameter, multiple tumors, lymph node metastasis, microvascular invasion, and perineural invasion. With propensity score matching, patients were divided into double-negative and non-double-negative groups, with 128 patients in each group, and the 5-year recurrence-free survival and overall survival rates were 33.8 vs 15.2 (P < 0.001) and 45.3 vs 19.0, respectively (P < 0.001). In the multivariate Cox analyses, double negativity for the 2 tumor markers was an independent factor for recurrence-free survival (hazard ratios, 0.578; 95% CI, 0.442–0.755, P < 0.001) and overall survival (hazard ratios, 0.567; 95% CI, 0.434–0.741, P < 0.001). DISCUSSION: Double negativity for CA19-9 and AFP indicated less invasive tumor characteristics in patients with ICC. Patients with double-negative tumor markers achieved better outcomes than those with non-double-negative markers, which is meaningful for prognostic counseling and therapeutic triage.

To select patients with hepatocellular carcinoma (HCC) for liver transplantation (LT), Milan criteria are still mainly used worldwide¹. Several selection criteria that sought to expand the Milan criteria have been proposed and acceptable post-LT survival may be obtained². However, none of the selection criteria challenged advanced HCC with macrovascular invasion. This is generally regarded as a contraindication for LT. Recently, several studies showed that combinations of locoregional and systemic treatment could significantly improve tumour response and overall survival for patients with advanced HCC^3–5. This included promising results of lenvatinib, transcatheter arterial chemoembolization (TACE) and programmed cell death protein 1 (PD-1) inhibitor (LEN-TAP) for advanced HCC⁶. With the improvement of combination therapy, the authors wondered whether LT could serve as another option for patients with advanced HCC after successful downstaging. The present study described the perioperative and postoperative outcome of patients who opted for LT when they failed to receive salvage liver resection due to decompensated liver function after successful downstaging.

STK39 is reportedly a critical negative regulator of intestinal barrier. Pharmacological targeting of STK39 is expected to protect the intestinal barrier and thereby weaken metabolic dysfunction-associated steatohepatitis (MASH); Proximal colon biopsy tissues from patients with metabolic dysfunction-associated steatotic liver disease (MASLD) and those without MASLD were analyzed for STK39 expression. Wildtype (WT) mice and systemic STK39 gene knockout (STK39-/-) male mice were fed a normal diet or a high-fat methionine-choline deficient diet (HFMCD) for 8 weeks. The MASH mice were grouped and treated with ZT-1a (a STK39 inhibitor) or vehicle intraperitoneal injection during the procedure of HFMCD induction. Liver and intestinal tissues were collected for further examination; Colon tissues from patients with MASLD exhibited higher levels of STK39 than those from subjects without MASLD. Knockout of STK39 diminished CD68+ Kupffer cells and α-SMA+ hepatic stellate cells infiltration in mouse MASH model. Treatment with ZT-1a also prevented severe steatohepatitis in a mouse MASH model, including milder histological and pathological manifestations (lobular inflammation and fibrosis) in the liver. Interestingly, Inhibition of STK39 had minimal effects on hepatic lipid metabolism. The reduced liver injury observed in mice with STK39 inhibition was linked to significant decreases in mucosal inflammation, tight junction disruption and intestinal epithelial permeability to bacterial endotoxins; Collectively, we have revealed that inhibiting STK39 prevents the progression of MASH by protecting the intestinal epithelial barrier.