Onco-fetal Reprogramming of Endothelial Cells Drives Immunosuppressive Macrophages in Hepatocellular Carcinoma.

We employed scRNA sequencing to extensively characterize the cellular landscape of human liver from development to disease. Analysis of ∼212,000 cells representing human fetal, hepatocellular carcinoma (HCC), and mouse liver revealed remarkable fetal-like reprogramming of the tumor microenvironment. Specifically, the HCC ecosystem displayed features reminiscent of fetal development, including re-emergence of fetal-associated endothelial cells (PLVAP/VEGFR2) and fetal-like (FOLR2) tumor-associated macrophages. In a cross-species comparative analysis, we discovered remarkable similarity between mouse embryonic, fetal-liver, and tumor macrophages. Spatial transcriptomics further revealed a shared onco-fetal ecosystem between fetal liver and HCC. Furthermore, gene regulatory analysis, spatial transcriptomics, and in vitro functional assays implicated VEGF and NOTCH signaling in maintaining onco-fetal ecosystem. Taken together, we report a shared immunosuppressive onco-fetal ecosystem in fetal liver and HCC. Our results unravel a previously unexplored onco-fetal reprogramming of the tumor ecosystem, provide novel targets for therapeutic interventions in HCC, and open avenues for identifying similar paradigms in other cancers and disease.

Early vs late drain removal after pancreatic resection-a systematic review and meta-analysis.

BACKGROUND: Reducing clinically relevant post-operative pancreatic fistula (CR-POPF) incidence after pancreatic resections has been a topic of great academic interest. Optimizing post-operative drain management is a potential strategy in reducing this major complication. METHODS: Studies involving pancreatic resections, including both pancreaticoduodenectomy (PD) and distal pancreatic resections (DP), with intra-operative drain placement were screened. Early drain removal was defined as removal before or on the 3rd post-operative day (POD) while late drain removal was defined as after the 3rd POD. The primary outcome was CR-POPF, International Study Group of Pancreatic Surgery (ISGPS) Grade B and above. Secondary outcomes were all complications, severe complications, post-operative haemorrhage, intra-abdominal infections, delayed gastric emptying, reoperation, length of stay, readmission, and mortality. RESULTS: Nine studies met the inclusion criteria and were included for analysis. The studies had a total of 8574 patients, comprising 1946 in the early removal group and 6628 in the late removal group. Early drain removal was associated with a significantly lower risk of CR-POPF (OR: 0.24, p < 0.01). Significant reduction in risk of post-operative haemorrhage (OR: 0.55, p < 0.01), intra-abdominal infection (OR: 0.35, p < 0.01), re-admission (OR: 0.63, p < 0.01), re-operation (OR: 0.70, p = 0.03), presence of any complications (OR: 0.46, p < 0.01), and reduced length of stay (SMD: -0.75, p < 0.01) in the early removal group was also observed. CONCLUSION: Early drain removal is associated with significant reductions in incidence of CR-POPF and other post-operative complications. Further prospective randomised trials in this area are recommended to validate these findings.

Targeting RNA editing of antizyme inhibitor 1: A potential oligonucleotide-based antisense therapy for cancer.

Dysregulated adenosine-to-inosine (A-to-I) RNA editing is implicated in various cancers. However, no available RNA editing inhibitors have so far been developed to inhibit cancer-associated RNA editing events. Here, we decipher the RNA secondary structure of antizyme inhibitor 1 (AZIN1), one of the best-studied A-to-I editing targets in cancer, by locating its editing site complementary sequence (ECS) at the 3' end of exon 12. Chemically modified antisense oligonucleotides (ASOs) that target the editing region of AZIN1 caused a substantial exon 11 skipping, whereas ECS-targeting ASOs effectively abolished AZIN1 editing without affecting splicing and translation. We demonstrate that complete 2'-O-methyl (2'-O-Me) sugar ring modification in combination with partial phosphorothioate (PS) backbone modification may be an optimal chemistry for editing inhibition. ASO3.2, which targets the ECS, specifically inhibits cancer cell viability in vitro and tumor incidence and growth in xenograft models. Our results demonstrate that this AZIN1-targeting, ASO-based therapeutics may be applicable to a wide range of tumor types.

Multimodal prehabilitation in older adults before major abdominal surgery: a systematic review and meta-analysis.

PURPOSE: Multimodal prehabilitation aims to prepare frail older patients for major surgery. The objective of this review is to determine the benefits of pre-operative multimodal prehabilitation compared to standard care in older patients. METHODS: Data sources included MEDLINE, EMBASE, CENTRAL, CINAHL and PsychINFO. They were searched from inception to September 2021. Only randomized controlled trials (RCT) with an average study population age ≥ 65 that had undergone major abdominal operation with at least two components (physical, nutritional, psychological) of prehabilitation programs were included. RESULTS: Nine RCTs were included with a total of 823 patients, of whom 705 completed the study with 358 undergoing prehabilitation and 347 were controls. Significantly lower complications were observed in the prehabilitation group compared to control (OR 0.67; 95% CI 0.46 to 0.99; p = 0.04; I2 = 32%). A significant increase in 6-min walking distance (6MWD) from baseline to immediately prior to surgery (mean difference 35.1 m; 95%CI 11.6-58.4; p = 0.003; I2 = 67%) and 8 weeks post-surgery (mean difference 44.9 m; 95%CI 6.0-83.8; p = 0.02; I2 = 75%) was noted in the prehabilitation group. No difference was observed in length of stay (OR 0.59; 95% CI - 0.23 to 1.40; p = 0.16; I2 = 91%) or 30-day emergency department visit (OR 0.72; 95% CI 0.41 to 1.26; p = 0.25; I2 = 0%). Patient reported outcome measures were not significantly different. CONCLUSIONS: Amongst older patients, multimodal prehabilitation increases peri-operative functional capacity and may potentially decrease post-operative complications. Future studies should continue to focus on older patients who are frail as this is the group that prehabilitation would likely have a clinically significant impact on.

An international multicenter study of protocols for liver transplantation during a pandemic: A case for quadripartite equipoise.

BACKGROUND & AIMS: The outbreak of COVID-19 has vastly increased the operational burden on healthcare systems worldwide. For patients with end-stage liver failure, liver transplantation is the only option. However, the strain on intensive care facilities caused by the pandemic is a major concern. There is an urgent need for ethical frameworks to balance the need for liver transplantation against the availability of national resources. METHODS: We performed an international multicenter study of transplant centers to understand the evolution of policies for transplant prioritization in response to the pandemic in March 2020. To describe the ethical tension arising in this setting, we propose a novel ethical framework, the quadripartite equipoise (QE) score, that is applicable to liver transplantation in the context of limited national resources. RESULTS: Seventeen large- and medium-sized liver transplant centers from 12 countries across 4 continents participated. Ten centers opted to limit transplant activity in response to the pandemic, favoring a "sickest-first" approach. Conversely, some larger centers opted to continue routine transplant activity in order to balance waiting list mortality. To model these and other ethical tensions, we computed a QE score using 4 factors - recipient outcome, donor/graft safety, waiting list mortality and healthcare resources - for 7 countries. The fluctuation of the QE score over time accurately reflects the dynamic changes in the ethical tensions surrounding transplant activity in a pandemic. CONCLUSIONS: This four-dimensional model of quadripartite equipoise addresses the ethical tensions in the current pandemic. It serves as a universally applicable framework to guide regulation of transplant activity in response to the increasing burden on healthcare systems. LAY SUMMARY: There is an urgent need for ethical frameworks to balance the need for liver transplantation against the availability of national resources during the COVID-19 pandemic. We describe a four-dimensional model of quadripartite equipoise that models these ethical tensions and can guide the regulation of transplant activity in response to the increasing burden on healthcare systems.

Laparoscopic versus open appendectomy in pediatric patients with complicated appendicitis: a meta-analysis.

BACKGROUND: Acute appendicitis is a common condition in the pediatric population. In patients with uncomplicated appendicitis, laparoscopic appendectomy (LA) is preferred as compared to open appendectomy (OA). However, in patients with complicated appendicitis (CA), as defined as suppurative, gangrenous or perforated appendicitis, or appendicitis with periappendicular abscess formation, the decision to perform OA or LA remains unclear. METHODS: The PRISMA guidelines were adhered to. An electronic database search from 1997 to 2017 was performed using the Cochrane, Medline, PubMed, Scopus, Ovid, Embase, and Web of Knowledge databases. Data analysis, including subgroup analysis of randomized-control trials, was performed using RevMan 5.3. Assessment of methodological and statistical heterogeneity, as well as publication bias of the included studies, was performed. RESULTS: Six randomized-control trials (296 LA versus 373 OA) and 33 case-control trials (3106 LA versus 4149 OA) were analyzed. Compared to OA, LA has a shorter length of stay (WMD = - 0.96, 95% CI - 1.47 to - 0.45) and a lower rate of surgical site infection (OR 0.37, 95% CI 0.25-0.54), although the rates of intraabdominal abscess formation were similar (OR 1.01, 95% CI 0.71-1.43). LA was also shown to have lower readmission rates, lower incidences of postoperative ileus or intestinal obstruction, lower incidence of reoperation, as well as a shorter time taken to oral intake. Operative time for OA was shorter than LA (WMD = 12.44, 95% CI 2.00-22.87). CONCLUSION: While studies in the past have associated LA with higher rates of intraabdominal abscess in patients with CA, our meta-analysis has shown that they were similar. Considering this, together with other improved postoperative outcomes, LA should be the procedure of choice in pediatric patients presenting with CA.

The influence of the middle hepatic vein and its impact on outcomes in right lobe living donor liver transplantation.

BACKGROUND: In adult right lobe living donor liver transplantation, the decision to include the middle hepatic vein (MHV) remains controversial. METHODS: A retrospective analysis of 50 R-LDLTs between January 2008 and June 2016 was performed. RESULTS: Twenty-one procedures were performed using a MHV+ graft (42.0%) and 29 procedures using a MHV- graft (58%). MHV- donors were taller (173 vs 166 cm, p = 0.004) with a larger standard liver volume (1351 vs 1245 mls, p = 0.014) compared to MHV+ donors. The duration of operation for donors was significantly longer in the MHV+ group (530 (313-975) mins) compared to the MHV- group (489 (336-708) mins) (p = 0.029). Similarly, the operative time for recipients was longer in the MHV+ group (660 (428-831) mins) compared to MHV- (579 (359-1214) mins) (p = 0.023). MHV- grafts were heavier compared to MHV+ grafts (918 vs 711 g, p = 0.017). Recipient mortality rates and Kaplan-Meier survival analysis were comparable (p = 0.411). All donors were well at last review. CONCLUSION: Both MHV+ and MHV- grafts are safe for the donor and recipient. The decision to take the MHV should be based on specific donor-recipient characteristics.

Does persistent anti-HBc positivity influence the prognosis of HBsAg-negative hepatocellular carcinoma? comparative outcomes of anti-Hbc positive versus anti-Hbc negative non-B non-C HCC.

BACKGROUND: To compare the presentations and outcomes of anti-HBc seropositive Hepatocellular Carcinoma (HBc-HCC) with anti-HBc seronegative (NHBc-HCC) patients in HBsAg negative Non-HBV Non-HCV (NBNC-HCC) HCC population. METHODS: 515 newly diagnosed HCC patients from January 2011 to September 2016 were retrospectively reviewed. 145 (66.5%) NHBc-HCC and 73 (33.5%) HBc-HCC patients were identified. Patient demographics, disease characteristics, details of treatments, recurrence and survival outcomes were analysed. RESULTS: A significantly lower proportion of HBc-HCC patients were diagnosed through surveillence (6.8% vs 26.2%, p = 0.001). HBc-HCC patients were less likely cirrhotic (p < 0.001), portal hypertensive (p < 0.001), ascitic (p = 0.008) and thrombocytopenic (p = 0.003). A higher proportion of HBc-HCC patients had treatment with curative intent (46.6% vs 30.3%, p = 0.018) and surgery (39.7% vs 16.6%, p < 0.001). Although HBc-HCC patients had larger median tumor size (74.0 mm vs 55.0 mm, p = 0.016) with a greater proportion of patients having tumors ≥5 cm, there was no difference in the overall median survival (19.0 months vs 22.0 months, p = 0.919) and recurrence rates (38.2% vs 40.9%). CONCLUSION: Isolated anti-HBc seropositivity in HbsAg negative patients tend to present incidentally with delayed diagnoses resulting in larger tumors, but their long-term survival remain comparable.

Development of a new patient-derived xenograft humanised mouse model to study human-specific tumour microenvironment and immunotherapy.

OBJECTIVE: As the current therapeutic strategies for human hepatocellular carcinoma (HCC) have been proven to have limited effectiveness, immunotherapy becomes a compelling way to tackle the disease. We aim to provide humanised mouse (humice) models for the understanding of the interaction between human cancer and immune system, particularly for human-specific drug testing. DESIGN: Patient-derived xenograft tumours are established with type I human leucocyte antigen matched human immune system in NOD-scid Il2rg-/- (NSG) mice. The longitudinal changes of the tumour and immune responses as well as the efficacy of immune checkpoint inhibitors are investigated. RESULTS: Similar to the clinical outcomes, the human immune system in our model is educated by the tumour and exhibits exhaustion phenotypes such as a significant declination of leucocyte numbers, upregulation of exhaustion markers and decreased the production of human proinflammatory cytokines. Notably, cytotoxic immune cells decreased more rapidly compared with other cell types. Tumour infiltrated T cells have much higher expression of exhaustion markers and lower cytokine production compared with peripheral T cells. In addition, tumour-associated macrophages and myeloid-derived suppressor cells are found to be highly enriched in the tumour microenvironment. Interestingly, the tumour also changes gene expression profiles in response to immune responses by upregulating immune checkpoint ligands. Most importantly, in contrast to the NSG model, our model demonstrates both therapeutic and side effects of immune checkpoint inhibitors pembrolizumab and ipilimumab. CONCLUSIONS: Our work provides a model for immune-oncology study and a useful parallel-to-human platform for anti-HCC drug testing, especially immunotherapy.

Splice-switch oligonucleotide-based combinatorial platform prioritizes synthetic lethal targets CHK1 and BRD4 against MYC-driven hepatocellular carcinoma.

Deregulation of MYC is among the most frequent oncogenic drivers in hepatocellular carcinoma (HCC). Unfortunately, the clinical success of MYC-targeted therapies is limited. Synthetic lethality offers an alternative therapeutic strategy by leveraging on vulnerabilities in tumors with MYC deregulation. While several synthetic lethal targets of MYC have been identified in HCC, the need to prioritize targets with the greatest therapeutic potential has been unmet. Here, we demonstrate that by pairing splice-switch oligonucleotide (SSO) technologies with our phenotypic-analytical hybrid multidrug interrogation platform, quadratic phenotypic optimization platform (QPOP), we can disrupt the functional expression of these targets in specific combinatorial tests to rapidly determine target-target interactions and rank synthetic lethality targets. Our SSO-QPOP analyses revealed that simultaneous attenuation of CHK1 and BRD4 function is an effective combination specific in MYC-deregulated HCC, successfully suppressing HCC progression in vitro. Pharmacological inhibitors of CHK1 and BRD4 further demonstrated its translational value by exhibiting synergistic interactions in patient-derived xenograft organoid models of HCC harboring high levels of MYC deregulation. Collectively, our work demonstrates the capacity of SSO-QPOP as a target prioritization tool in the drug development pipeline, as well as the therapeutic potential of CHK1 and BRD4 in MYC-driven HCC.

Safely Implementing a Program of Pure Laparoscopic Donor Right Hepatectomy: The Experience From a Southeast Asian Center.

Laparoscopic donor right hepatectomy (LDRH) is a technically challenging procedure. There is increasing evidence demonstrating the safety of LDRH in high-volume expert centers. We report our center's experience in implementing an LDRH program in a small- to medium-sized transplantation program. Methods: Our center systematically introduced a laparoscopic hepatectomy program in 2006. We started with minor wedge resections followed by major hepatectomies with increasing complexities. In 2017, we performed our first laparoscopic living donor left lateral sectionectomy. Since 2018, we have performed 8 cases of right lobe living donor hepatectomy (laparoscopy-assisted: 4 and pure laparoscopic: 4). Results: The median operative time was 418 (298-540) min, whereas the median blood loss was 300 (150-900) mL. Two patients (25%) had surgical drain placed intraoperatively. The median length of stay was 5 (3-8) d, and the median time to return to work was 55 (24-90) d. None of the donors sustained any long-term morbidity or mortality. Conclusions: Small- to medium-sized transplant programs face unique challenges in adopting LDRH. Progressive introduction of complex laparoscopic surgery, a mature living donor liver transplantation program, appropriate patient selection, and the invitation of an expert to proctor the LDRH are necessary to ensure success.

NanoBeacon.AI: AI-Enhanced Nanodiamond Biosensor for Automated Sensitivity Prediction to Oxidative Phosphorylation Inhibitors.

Spalt-like transcription factor 4 (SALL4) is an oncofetal protein that has been identified to drive cancer progression in hepatocellular carcinoma (HCC) and hematological malignancies. Furthermore, a high SALL4 expression level is correlated to poor prognosis in these cancers. However, SALL4 lacks well-structured small-molecule binding pockets, making it difficult to design targeted inhibitors. SALL4-induced expression of oxidative phosphorylation (OXPHOS) genes may serve as a therapeutically targetable vulnerability in HCC through OXPHOS inhibition. Because OXPHOS functions through a set of genes with intertumoral heterogeneous expression, identifying therapeutic sensitivity to OXPHOS inhibitors may not rely on a single clear biomarker. Here, we developed a workflow that utilized molecular beacons, nucleic-acid-based, activatable sensors with high specificity to the target mRNA, delivered by nanodiamonds, to establish an artificial intelligence (AI)-assisted platform for rapid evaluation of patient-specific drug sensitivity. Specifically, when the HCC cells were treated with the nanodiamond-medicated OXPHOS biosensor, high sensitivity and specificity of the sensor allowed for improved identification of OXPHOS expression in cells. Assisted by a trained convolutional neural network, drug sensitivity of cells toward an OXPHOS inhibitor, IACS-010759, could be accurately predicted. AI-assisted OXPHOS drug sensitivity assessment could be accomplished within 1 day, enabling rapid and efficient clinical decision support for HCC treatment. The work proposed here serves as a foundation for the patient-based subtype-specific therapeutic research platform and is well suited for precision medicine.

Histone-lysine N-methyltransferase EHMT2 (G9a) inhibition mitigates tumorigenicity in Myc-driven liver cancer.

Hepatocellular carcinoma (HCC) is the third deadliest and sixth most common cancer in the world. Histone-lysine N-methyltransferase EHMT2 (also known as G9a) is a histone methyltransferase frequently overexpressed in many cancer types, including HCC. We showed that Myc-driven liver tumours have a unique H3K9 methylation pattern with corresponding G9a overexpression. This phenomenon of increased G9a was further observed in our c-Myc-positive HCC patient-derived xenografts. More importantly, we showed that HCC patients with higher c-Myc and G9a expression levels portend a poorer survival with lower median survival months. We demonstrated that c-Myc interacts with G9a in HCC and cooperates to regulate c-Myc-dependent gene repression. In addition, G9a stabilises c-Myc to promote cancer development, contributing to the growth and invasive capacity in HCC. Furthermore, combination therapy between G9a and synthetic-lethal target of c-Myc, CDK9, demonstrates strong efficacy in patient-derived avatars of Myc-driven HCC. Our work suggests that targeting G9a could prove to be a potential therapeutic avenue for Myc-driven liver cancer. This will increase our understanding of the underlying epigenetic mechanisms of aggressive tumour initiation and lead to improved therapeutic and diagnostic options for Myc-driven hepatic tumours.

Injectable liposomal docosahexaenoic acid alleviates atherosclerosis progression and enhances plaque stability.

Atherosclerosis is a chronic inflammatory vascular disease that is characterized by the accumulation of lipids and immune cells in plaques built up inside artery walls. Docosahexaenoic acid (DHA, 22:6n-3), an omega-3 polyunsaturated fatty acid (PUFA), which exerts anti-inflammatory and antioxidant properties, has long been purported to be of therapeutic benefit to atherosclerosis patients. However, large clinical trials have yielded inconsistent data, likely due to variations in the formulation, dosage, and bioavailability of DHA following oral intake. To fully exploit its potential therapeutic effects, we have developed an injectable liposomal DHA formulation intended for intravenous administration as a plaque-targeted nanomedicine. The liposomal formulation protects DHA against chemical degradation and increases its local concentration within atherosclerotic lesions. Mechanistically, DHA liposomes are readily phagocytosed by activated macrophages, exert potent anti-inflammatory and antioxidant effects, and inhibit foam cell formation. Upon intravenous administration, DHA liposomes accumulate preferentially in atherosclerotic lesional macrophages and promote polarization of macrophages towards an anti-inflammatory M2 phenotype, resulting in attenuation of atherosclerosis progression in both ApoE-/- and Ldlr-/- experimental models. Plaque composition analysis demonstrates that liposomal DHA inhibits macrophage infiltration, reduces lipid deposition, and increases collagen content, thus improving the stability of atherosclerotic plaques against rupture. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) further reveals that DHA liposomes can partly restore the complex lipid profile of the plaques to that of early-stage plaques. In conclusion, DHA liposomes offer a promising approach for applying DHA to stabilize atherosclerotic plaques and attenuate atherosclerosis progression, thereby preventing atherosclerosis-related cardiovascular events.

Elevated Urinary Tissue Inhibitor of Metalloproteinase-2 and Insulin-Like Growth Factor Binding Protein-7 Predict Drug-Induced Acute Kidney Injury.

BACKGROUND: Urinary tissue inhibitor of metalloproteinase-2 (TIMP2) and insulin-like growth factor binding protein-7 (IGFBP7) predict severe acute kidney injury (AKI) in critical illness. Earlier but subtle elevation of either biomarker from nephrotoxicity may predict drug-induced AKI. METHODS: A prospective study involving serial urine collection in patients treated with vancomycin, aminoglycosides, amphotericin, foscarnet, or calcineurin inhibitors was performed. Urinary TIMP2 and IGFBP7, both absolute levels and those normalized with urine creatinine, were examined in days leading to AKI onset by KDIGO criteria in cases or at final day of nephrotoxic therapy in non-AKI controls, who were matched for age, baseline kidney function, and nephrotoxic exposure. RESULTS: Urinary biomarker analyses were performed in 21 AKI patients and 28 non-AKI matched-controls; both groups had comparable baseline kidney function and duration of nephrotoxic drug therapy. Significantly higher absolute, normalized, and composite levels of TIMP2 and IGFBP7 were observed in AKI cases versus controls as early as 2-3 days before AKI onset (all P<0.05); >70% of patients with corresponding levels above 75th percentile developed AKI. Normalized TIMP2 at 2-3 days pre-AKI predicted AKI with the highest average AUROC of 0.81, followed by that of composite [TIMP2]x[IGFBP7] (0.78) after cross-validation. [TIMP2]x[IGFBP7] >0.01 (ng/mL)2/1000 predicted AKI with a sensitivity of 79% and specificity of 60%. CONCLUSION: Elevated urinary TIMP2 or IGFBP7 predicts drug-induced AKI with a lead-time of 2-3 days; an opportune time for interventions to reduce nephrotoxicity.

Impact of donor age on recipient morbidity and mortality after living donor liver transplantation.

BACKGROUND: Evidence for use of graft from older donors in living donor liver transplantation (LDLT) has been conflicting. This study aims to clarify the impact of donor age on recipient morbidity and mortality after adult LDLT. METHODS: A total of 90 live liver donors and recipients who underwent primary adult-to-adult LDLT were divided into three groups according to donor age: donors in 20s (D-20s) group, donors in 30s and 40s (D-30s and 40s) group and donors in 50s & 60s (D-50s and 60s) group. Multivariate analyses were conducted to look for independent risk/prognostic factors. Donor age was analysed as a continuous variable to determine an optimal cut off. RESULTS: Overall donor morbidity was 4/90 (4.44%), major donor morbidity was 1/90 (1.11%) and there was no donor mortality. Recipients in the D-20s group had better 1-, 3- and 5-year recipient survival than recipients in the D-50s and 60s group (96%, 91%, 91% versus 73%, 58%, 58%, respectively) (P = 0.020). Donor age was identified to be an independently significant risk factor for increased major complications (P = 0.007) and prognostic factor for reduced overall survival (P = 0.014). The optimal donor age cut off was determined to be 46.5 years old. CONCLUSION: Older donors are associated with poorer recipient outcomes after adult-to-adult LDLT. Usage of liver grafts from older donors should be carefully considered when choosing liver grafts for patients undergoing LDLT.

Pan-cancer pervasive upregulation of 3' UTR splicing drives tumourigenesis.

Most mammalian genes generate messenger RNAs with variable untranslated regions (UTRs) that are important post-transcriptional regulators. In cancer, shortening at 3' UTR ends via alternative polyadenylation can activate oncogenes. However, internal 3' UTR splicing remains poorly understood as splicing studies have traditionally focused on protein-coding alterations. Here we systematically map the pan-cancer landscape of 3' UTR splicing and present this in SpUR ( http://www.cbrc.kaust.edu.sa/spur/home/ ). 3' UTR splicing is widespread, upregulated in cancers, correlated with poor prognosis and more prevalent in oncogenes. We show that antisense oligonucleotide-mediated inhibition of 3' UTR splicing efficiently reduces oncogene expression and impedes tumour progression. Notably, CTNNB1 3' UTR splicing is the most consistently dysregulated event across cancers. We validate its upregulation in hepatocellular carcinoma and colon adenocarcinoma, and show that the spliced 3' UTR variant is the predominant contributor to its oncogenic functions. Overall, our study highlights the importance of 3' UTR splicing in cancer and may launch new avenues for RNA-based anti-cancer therapeutics.