SY-1530, a highly selective BTK inhibitor, effectively treats B-cell malignancies by blocking B-cell activation

Objective:B-cell antigen receptor(BCR)signaling is required to maintain the physiological functions of normal B cells and plays an important pathogenic role in B-cell malignancies.Bruton tyrosine kinase(BTK),a critical mediator of BCR signaling,is an attractive target for the treatment of B-cell malignancies.This study aimed to identify a highly potent and selective BTK inhibitor.Methods:Homogeneous time-resolved fluorescence assays were used to screen BTK inhibitors.Typhoon fluorescence imaging and Western blot analysis were used to confirm the effects of SY-1530 on the BCR signaling pathway.Additionally,the anti-tumor activities of SY-1530 were evaluated in TMD8 xenografts and spontaneous canine B-cell lymphoma.Results:We found a novel irreversible and non-competitive inhibitor of BTK,SY-1530,which provided dose-dependent and timedependent inhibition.SY-1530 selectively bound to BTK rather than inducible T-cell kinase;consequently,it did not significantly affect T-cell receptor signaling and caused limited off-target effects.SY-1530 blocked the BCR signaling pathway through downregulation of BTK activity,thus leading to impaired phosphorylation of BTK and its downstream kinases.Moreover,SY-1530 induced apoptosis in a caspase-dependent manner and efficaciously inhibited tumor growth in mouse xenograft models of B-cell malignancy(P<0.001).SY-1530 also induced positive clinical responses in spontaneous canine B-cell lymphoma.Conclusions:SY-1530 is an irreversible and selective BTK inhibitor that shows inhibitory effects on B-cell malignancies by blocking the BCR signaling pathway.Therefore,it may be a promising therapeutic approach for the treatment of B-cell malignancies.

Culturing adequate CAR-T cells from less peripheral blood to treat B-cell malignancies

Objective:Chimeric antigen receptor-modified T(CAR-T)cells have shown impressive results against relapsed/refractory B cell malignancies.However,the traditional manufacture of CAR-T cells requires leukapheresis to isolate large amounts of peripheral blood T cells,thus making some patients ineligible for the procedure.Methods:We developed a simple method for CAR-T cell preparation requiring small volumes of peripheral blood.First,CD3+T cells isolated from 50 mL peripheral blood from patients(B-cell malignancies)were stimulated with immobilized anti-CD3/RetroNectin in 6-well plates and then transduced with CAR-expressing lentiviral vector.After 4 d,the T cells were transferred to culture bags for large-scale CAR-T cell expansion.In vitro and animal experiments were performed to evaluate the activity of the manufactured CAR-T cells.Finally,29 patients with B-cell acute lymphoblastic leukemia(B-ALL)and 9 patients with B-cell lymphoma were treated with the CAR-T cells.Results:The CAR-T cells were expanded to 1–3×10^(8) cells in 8–10 d and successfully killed B cell-derived malignant tumor cells in vitro and in vivo.For patients with B-ALL,the complete remission rate was 93%1 month after CAR-T cell infusion;after 12 months,the overall survival(OS)and leukemia-free survival rates were 69%and 31%,respectively.For patients with lymphoma,the objective response rate(including complete and partial remission)was 78%2 months after CAR-T cell infusion,and after 12 months,the OS and progression-free survival rates were 71%and 43%,respectively.Cytokine-release syndrome(CRS)occurred in 65.51%and 55.56%of patients with B-ALL and B-cell lymphoma,respectively;severe CRS developed in 20.69%of patients with B-ALL and in no patients with lymphoma.Conclusions:Our novel method can generate sufficient numbers of CAR-T cells for clinical use from 50–100 mL peripheral blood,thus providing an alternative means of CAR-T cell generation for patients ineligible for leukapheresis.

Modulation of B-cell receptor and microenvironment signaling by a guanine exchange factor in B-cell malignancies

Objective： Chronic lymphocytic leukemia （CLL） and mantle cell lymphoma （MCL） cells over-express a guanine exchange factor （GEF）, Rasgrf-1. This GEF increases active Ras as it catalyzes the removal of GDP from Ras so that GTP can bind and activate Ras. This study aims to study the mechanism of action of Rasgrf-1 in B-cell malignancies. Methods： N-terminus truncated Rasgrf-1 variants have a higher GEF activity as compared to the full-length transcript therefore a MCL cell line with stable over-expression of truncated Rasgrf-1 was established. The B-cell receptor （BCR） and chemokine signaling pathways were compared in the Rasgrf-I over-expressing and a control transfected cell line. Results： Cells over-expressing truncated form of Rasgrf-1 have a higher proliferative rate as compared to control transfected cells. BCR was activated by lower concentrations of anti-IgM antibody in Rasgrf-1 over-expressing cells as compared to control cells indicating that these cells are more sensitive to BCR signaling. BCR signaling also phosphorylates Rasgrf-1 that further increases its GEF function and amplifies BCR signaling. This activation of Rasgrf-1 in over-expressing cells resulted in a higher expression of phospho-ERK, AKT, BTK and PKC-alpha as compared to control cells. Besides BCR, Rasgrf-1 over-expressing cells were also more sensitive to microenvironment stimuli as determined by resistance to apoptosis, chemotaxis and ERK pathway activation. Conclusions： This GEF protein sensitizes B-cells to BCR and chemokine mediated signaling and also upregulates a number of other signaling pathways which promotes growth and survival of these cells.

Preclinical evaluation of cyclophosphamide and fludarabine combined with CD19 CAR-T in the treatment of B-cell hematologic malignancies in vivo

Background:Chimeric antigen receptor T(CAR-T)cell therapy has achieved marked therapeutic success in ameliorating hematological malignancies.However,there is an extant void in the clinical guidelines concerning the most effective chemotherapy regimen prior to chimeric antigen receptor T(CAR-T)cell therapy,as well as the optimal timing for CAR-T cell infusion post-chemotherapy.Materials and Methods:We employed cell-derived tumor xenograft(CDX)murine models to delineate the optimal pre-conditioning chemotherapy regimen and timing for CAR-T cell treatment.Furthermore,transcriptome sequencing was implemented to identify the therapeutic targets and elucidate the underlying mechanisms governing the treatment regimen.Results:Our preclinical in vivo evaluation determined that a combination of cyclophosphamide and fludarabine,followed by the infusion of CD19 CAR-T cells five days subsequent to the chemotherapy,exerts the most efficacious therapeutic effect in B-cell hematological malignancies.Concurrently,RNA-seq data indicated that the therapeutic efficacy predominantly perturbs tumor cell metabolism,primarily through the inhibition of key mitochondrial targets,such as C-Jun Kinase enzyme(C-JUN).Conclusion:In summary,the present study offers critical clinical guidance and serves as an authoritative reference for the deployment of CD19 CAR-T cell therapy in the treatment of B-cell hematological malignancies.

Relapse after CAR-T cell therapy in B-cell malignancies: challenges and future approaches

Chimeric antigen receptor-T(CAR-T)cell therapy,as a novel cellular immunotherapy,has dramatically reshaped the landscape of cancer treatment,especially in hematological malignancies.However,relapse is still one of the most troublesome obstacles to achieving broad clinical application.The intrinsic factors and superior adaptability of tumor cells mark a fundamental aspect of relapse.The unique biological function of CAR-T cells governed by their special CAR construction also affects treatment efficacy.Moreover,complex cross-interactions among CAR-T cells,tumor cells,and the tumor microenvironment(TME)profoundly influence clinical outcomes concerning CAR-T cell function and persistence.Therefore,in this review,based on the most recent discoveries,we focus on the challenges of relapse after CAR-T cell therapy in B-cell malignancies from the perspective of tumor cells,CAR-T cells,and the TME.We also discuss the corresponding basic and clinical approaches that may overcome the problem in the future.We aim to provide a comprehensive understanding for scientists and physicians that will help improve research and clinical practice.

Ex vivo liver resection and auto-transplantation as an alternative for the treatment of liver malignancies: Progress and challenges

Hepatectomy is still the major curative treatment for patients with liver malignancies.However,it is still a big challenge to remove the tumors in the central posterior area,especially if their location involves the retrohepatic inferior vena cava and hepatic veins.Ex vivo liver resection and auto-transplantation(ELRA),a hybrid technique of the traditional liver resection and transplantation,has brought new hope to these patients and therefore becomes a valid alternative to liver transplantation.Due to its technical difficulty,ELRA is still concentrated in a few hepatobiliary centers that have experienced surgeons in both liver resection and liver transplantation.The efficacy and safety of this technique has already been demonstrated in the treatment of benign liver diseases,especially in the advanced alveolar echinococcosis.Recently,the application of ELRA for liver malignances has gained more attention.However,standardization of clinical practice norms and international consensus are still lacking.The prognostic impact in these oncologic patients also needs further evaluation.In this review,we summarized the principles and recent progresses on ELRA.

Blockade of CD300A enhances the ability of human NK cells to lyse hematologic malignancies

Objective: The human cluster of differentiation(CD)300A, a type-I transmembrane protein with immunoreceptor tyrosine-based inhibitory motifs, was investigated as a potential immune checkpoint for human natural killer(NK) cells targeting hematologic malignancies(HMs).Methods: We implemented a stimulation system involving the CD300A ligand, phosphatidylserine(PS), exposed to the outer surface of malignant cells. Additionally, we utilized CD300A overexpression, a CD300A blocking system, and a xenotransplantation model to evaluate the impact of CD300A on NK cell efficacy against HMs in in vitro and in vivo settings. Furthermore, we explored the association between CD300A and HM progression in patients.Results: Our findings indicated that PS hampers the function of NK cells. Increased CD300A expression inhibited HM lysis by NK cells. CD300A overexpression shortened the survival of HM-xenografted mice by impairing transplanted NK cells. Blocking PS–CD300A signals with antibodies significantly amplified the expression of lysis function-related proteins and effector cytokines in NK cells, thereby augmenting the ability to lyse HMs. Clinically, heightened CD300A expression correlated with shorter survival and an “exhausted” phenotype of intratumoral NK cells in patients with HMs or solid tumors.Conclusions: These results propose CD300A as a potential target for invigorating NK cell-based treatments against HMs.

Selective internal radiation therapy segmentectomy:A new minimally invasive curative option for primary liver malignancies?

Transarterial radioembolization or selective internal radiation therapy(SIRT)has emerged as a minimally invasive approach for the treatment of tumors.This percutaneous technique involves the local,intra-arterial delivery of radioactive microspheres directly into the tumor.Historically employed as a palliative measure for liver malignancies,SIRT has gained traction over the past decade as a potential curative option,mirroring the increasing role of radiation segmentectomy.The latest update of the BCLC hepatocellular carcinoma guidelines recognizes SIRT as an effective treatment modality comparable to other local ablative methods,particularly well-suited for patients where surgical resection or ablation is not feasible.Radiation segmentectomy is a more selective approach,aiming to deliver high-dose radiation to one to three specific hepatic segments,while minimizing damage to surrounding healthy tissue.Future research efforts in radiation segmentectomy should prioritize optimizing radiation dosimetry and refining the technique for super-selective administration of radiospheres within the designated hepatic segments.

Identification of NOXA as a pivotal regulator of resistance to CAR T-cell therapy in B-cell malignancies

Despite the remarkable success of chimeric antigen receptor(CAR)T-cell therapy for treating hematologic malignancies,resistance and recurrence still occur,while the markers or mechanisms underlying this resistance remain poorly understood.Here,via an unbiased genome-wide CRISPR/Cas9 screening,we identified loss of NOXA,a B-cell lymphoma 2(BCL2)family protein in B-cell malignancies,as a pivotal regulator of resistance to CAR T-cell therapy by impairing apoptosis of tumor cells both in vitro and in vivo.Notably,low NOXA expression in tumor samples was correlated with worse survival in a tandem CD19/20 CAR T clinical trial in relapsed/refractory B-cell lymphoma.

CAR T-cell immunotherapy: a powerful weapon for fighting hematological B-cell malignancies

The current standard of care in hematological malignancies has brought considerable clinical benefits to patients.However,important bottlenecks still limit optimal achievements following a current medical practice.The genetic complexity of the diseases and the heterogeneity of tumor clones cause difficulty in ensuring long-term efficacy of conventional treatments for most hematological disorders.Consequently,new treatment strategies are necessary to improve clinical outcomes.Chimeric antigen receptor T-cell(CAR T)immunotherapy opens a new path for targeted therapy of hematological malignancies.In this review,through a representative case study,we summarize the current experience of CAR T-cell therapy,the management of common side effects,the causative mechanisms of therapy resistance,and new strategies to improve the efficacy of CAR T-cell therapy.

Application of Fusobacterium nucleatum as a biomarker in gastrointestinal malignancies

The morbidity and mortality of gastrointestinal(GI)malignancies are among the highest in the world,posing a serious threat to human health.Because of the insidious onset of the cancer,it is difficult for patients to be diagnosed at an early stage,and it rapidly progresses to an advanced stage,resulting in poor treatment and prognosis.Fusobacterium nucleatum(F.nucleatum)is a gram-negative,sporefree anaerobic bacterium that primarily colonizes the oral cavity and is implicated in the development of colorectal,esophageal,gastric,and pancreatic cancers via various intricate mechanisms.Recent development in novel research suggests that F.nucleatum may function as a biomarker in GI malignancies.Detecting the abundance of F.nucleatum in stool,saliva,and serum samples of patients may aid in the diagnosis,risk assessment,and prognosis monitoring of GI malignancies.This editorial systematically describes the biological roles and mechanisms of F.nucleatum in GI malignancies focusing on the application of F.nucleatum as a biomarker in the diagnosis and prognosis of GI malignancies to promote the clinical translation of F.nucleatum and GI tumors-related research.

Hematological Malignancies in Sickle Cell Disease Patients: Report of Four Cases in Togo and Literature Review

Background: Hemopathies were rarely observed in major sickle cell disease patients some thirty years ago, probably due to the high mortality rate among the latter as a result of progressive complications. Thanks to advances in the management of sickle cell disease, patients' life expectancy has increased considerably, exposing them more frequently to neoplasia, including hematological malignancies. The increased risk of leukemogenesis is multifactorial and linked to the pathophysiological mechanisms of the clinical manifestations of sickle cell disease. Study Setting: The clinical haematology department of campus teaching hospital and the paediatric onco-haematology unit of Sylvanus Olympio teaching hospital in Lomé were used as study settings. Observations: Four hematologic malignancies were collected in a cohort of 5847 major sickle cell syndromes. The median age of the patients was 31.25 years (extremes: 14 and 58 years) and they were predominantly female (sex ratio M/F = 0.25). Two were on background therapy with hydroxyurea. Among the four patients, there were two cases of acute lymphocytic leukemia, including ALL3 in a 58-year-old SS woman and T-ALL2 in a 12-year-old SC. Then, a case of lymphocytic lymphoma in a 20-year-old SS man was reported and finally a case of chronic myelocytic leukemia in a 33-year-old woman of Sβ+ thalassaemia phenotype. Conclusion: To further report this coexistence, it is therefore essential to systematically consider hematological malignancies during major sickle cell syndromes even if there are similarities in the symptomatology of these two serious pathological situations.

Analysis of sleep quality,disease uncertainty,and psychological tolerance in patients undergoing chemotherapy for digestive tract malignancies

BACKGROUND Colorectal cancer is the second leading cause of cancer-related deaths among digestive tract malignancies,following gastric cancer.Sleep is of great significance for maintaining human health.The incidence of sleep disorders in patients with cancer is approximately twice that observed in the general population.Lack of sleep can prolong hospital stays,increase the likelihood of infection,and increase mortality rates.Therefore,studying the factors related to sleep quality is significant for improving the quality of life of patients with malignant tumors of the digestive tract.AIM To investigate the relationships among sleep quality,disease uncertainty,and psychological resilience in patients undergoing chemotherapy for digestive tract malignancies.METHODS A total of 131 patients with malignant digestive tract tumors who were treated at Hefei BOE Hospital between April 2021 and September 2022 were selected as research participants.Based on their Pittsburgh Sleep Quality Index(PSQI)scores,participants were divided into either the sleep disorder group(PSQI score>7)or the normal sleep group(PSQI score≤7).The clinical data—together with the Mishel Uncertainty in Illness Scale for Adults(MUIS-A)and Connor-Davidson Resilience Scale(CD-RISC)scores—were compared.RESULTS In this study,78(59.54%)patients with digestive tract malignancies developed sleep disorders after chemotherapy.Sleep disorder incidence was higher in patients with colorectal cancer than in those with gastric and esophageal cancers(P<0.05).The total MUIS-A score and those for each item in the sleep disorder group were higher than those in the normal sleep group.The total CD-RISC score and those for each item in the sleep disorder group were lower than those in the normal sleep group(P<0.05).The PSQI scores of patients with malignant digestive tract tumors were positively correlated with the scores for lack of disease information,disease uncertainty,and unpredictability in the MUIS-A and negatively correlated with the scores for tenacity,self-improvement,and optimism in the CD-RISC(P<0.05).CONCLUSION Patients undergoing chemotherapy for digestive tract malignancies are prone to sleep problems related to disease uncertainty and psychological resilience.Therefore,interventions can be implemented to improve their sleep quality.

Prevention of hepatitis B reactivation in patients with hematologic malignancies treated with novel systemic therapies:Who and Why?

The risk of reactivation in patients with chronic or past/resolved hepatitis B virus(HBV)infection receiving chemotherapy or immunosuppressive drugs is a wellknown possibility.The indication of antiviral prophylaxis with nucleo(t)side analogue is given according to the risk of HBV reactivation of the prescribed therapy.Though the advent of new drugs is occurring in all the field of medicine,in the setting of hematologic malignancies the last few years have been characterized by several drug classes and innovative cellular treatment.As novel therapies,there are few data about the rate of HBV reactivation and the decision of starting or not an antiviral prophylaxis could be challenging.Moreover,patients are often treated with a combination of different drugs,so evaluating the actual role of these new therapies in increasing the risk of HBV reactivation is difficult.First results are now available,but further studies are still needed.Patients with chronic HBV infection[hepatitis B surface antigen(HBsAg)positive]are reasonably all treated.Past/resolved HBV patients(HBsAg negative)are the actual area of uncertainty where it could be difficult choosing between prophylaxis and pre-emptive strategy.

Impact of artificial intelligence in the management of esophageal,gastric and colorectal malignancies

The incidence of gastrointestinal malignancies has increased over the past decade at an alarming rate.Colorectal and gastric cancers are the third and fifth most commonly diagnosed cancers worldwide but are cited as the second and third leading causes of mortality.Early institution of appropriate therapy from timely diagnosis can optimize patient outcomes.Artificial intelligence(AI)-assisted diagnostic,prognostic,and therapeutic tools can assist in expeditious diagnosis,treatment planning/response prediction,and post-surgical prognostication.AI can intercept neoplastic lesions in their primordial stages,accurately flag suspicious and/or inconspicuous lesions with greater accuracy on radiologic,histopathological,and/or endoscopic analyses,and eliminate over-dependence on clinicians.AI-based models have shown to be on par,and sometimes even outperformed experienced gastroenterologists and radiologists.Convolutional neural networks(state-of-the-art deep learning models)are powerful computational models,invaluable to the field of precision oncology.These models not only reliably classify images,but also accurately predict response to chemotherapy,tumor recurrence,metastasis,and survival rates post-treatment.In this systematic review,we analyze the available evidence about the diagnostic,prognostic,and therapeutic utility of artificial intelligence in gastrointestinal oncology.

Stage IV malignant transformation of mature cystic teratoma palliatively treated with concurrent chemoradiotherapy:A case report

BACKGROUND Malignant transformation(MT)of mature cystic teratoma(MCT)has a poor prognosis,especially in advanced cases.Concurrent chemoradiotherapy(CCRT)has an inhibitory effect on MT.CASE SUMMARY Herein,we present a case in which CCRT had a reduction effect preoperatively.A 73-year-old woman with pyelonephritis was referred to our hospital.Computed tomography revealed right hydronephrosis and a 6-cm pelvic mass.Endoscopic ultrasound-guided fine-needle biopsy(EUS-FNB)revealed squamous cell carci-noma.The patient was diagnosed with MT of MCT.Due to her poor general con-dition and renal malfunction,we selected CCRT,expecting fewer adverse effects.After CCRT,her performance status improved,and the tumor size was reduced;surgery was performed.Five months postoperatively,the patient developed dis-semination and lymph node metastases.Palliative chemotherapy was ineffective.She died 18 months after treatment initiation.CONCLUSION EUS-FNB was useful in the diagnosis of MT of MCT;CCRT suppressed the disea-se and improved quality of life.

Can Emax and platelet count truly differentiate between benign and malignant liver lesions?

This letter critically evaluates Jiang et al's article on the differentiation of benign and malignant liver lesions using Emax and platelet count.Despite notable findings,significant methodological and interpretative limitations are identified.The study lacks detailed assay conditions for Emax measurement,employs inadequate statistical methods without robust multivariate analysis,and does not provide clinically relevant threshold values.The nomogram's reliance on Emax as a major diagnostic contributor is questionable due to attenuation in hepatocellular carcinoma patients with cirrhosis.Moreover,the study's limitations,such as selection bias and confounding factors,are not adequately addressed.Future research should adopt more rigorous methodologies,including prospective studies with larger cohorts and standardized protocols for biomarker measurement,to enhance validity and clinical applicability.

Extrapancreatic malignancies and intraductal papillary mucinous neoplasms of the pancreas

Over the last two decades multiple studies have demonstrated an increased incidence of additional malignancies in patients with intraductal papillary mucinous neoplasms(IPMNs).Additional malignancies have been identified in 10%-52% of patients with IPMNs.The majority of these additional cancers occur before or concurrent with the diagnosis of IPMN.The gastrointestinal tract is most commonly involved in secondary malignancies,with benign colon polyps and colon cancer commonly seen in western countries and gastric cancer commonly seen in Asian countries.Other extrapancreatic malignancies associated with IPMNs include benign and malignant esophageal neoplasms,gastrointestinal stromal tumors,carcinoid tumors,hepatobiliary cancers,breast cancers,prostate cancers,and lung cancers.There is no clear etiology for the development of secondary malignancies in patients with IPMN.Although population-based studies have shown different results from single institution studies regarding the exact incidence of additional primary cancers in IPMN patients,both have reached the same conclusion:there is a higher incidence of extrapancreatic malignancies in patients with IPMNs than in the general population.This f inding has signif icant clinical implications for both the initial evaluation and the subsequent long-term followup of patients with IPMNs.If a patient has not had recent colonoscopy,this should be performed during the evaluation of a newly diagnosed IPMN.Upper endoscopy should be performed in patients from Asian countries or for those who present with symptoms suggestive of upper gastrointestinal disease.Routine screening studies(breast and prostate) should be carried out as currently recommended for patient's age both before and after the diagnosis of IPMN.

Incidence, risk factors and outcomes of de novo malignancies post liver transplantation

Liver transplantation(LT) is associated with a 2 to7 fold higher, age and gender adjusted, risk of de novo malignancy. The overall incidence of de novo malignancy post LT ranges from 2.2% to 26%, and 5 and 10 years incidence rates are estimated at 10% to 14.6% and 20% to 32%, respectively. The main risk factors for de novo malignancy include immunosuppression with impaired immunosurveillance, and a number of patient factors which include; age, latent oncogenic viral infections, tobacco and alcohol use history, and underlying liver disease. The most common cancers after LT are non-melanoma skin cancers, accounting for approximately 37% of de novo malignancies, with a noted increase in the ratio of squamous to basal cell cancers. While these types of skin cancer do not impact patient survival, post-transplant lymphoproliferative disorders and solid organ cancer, accounting for 25% and 48% of malignancies, are associated with increased mortality. Patients developing these types of cancer are diagnosed at more advanced stages, and their cancers behave more aggressively compared with the general population. Patients undergoing LT for primary sclerosing cholangitis(particularly with inflammatory bowel disease) and alcoholic liver disease have high rates of malignancies compared with patients undergoing LT for other indications. These populations are at particular risk for gastrointestinal and aerodigestive cancers respectively. Counseling smoking cessation, skin protection from sun exposure and routine clinical follow-up are the current approach in practice. There are no standardized surveillance protocol, but available data suggests that regimented surveillance strategies are needed and capable of yielding cancer diagnosis at earlier stages with better resulting survival. Evidence-based strategies are needed to guide optimal surveillance and safe minimization of immunosuppression.

E2F transcription factors and digestive system malignancies: How much do we know?

E2F family of transcription factors regulates various cellular functions related to cell cycle and apoptosis. Its individual members have traditionally been classified into activators and repressors, based on in vitro studies. However their contribution in human cancer is more complicated and difficult to predict. We review current knowledge on the expression of E2Fs in digestive system malignancies and its clinical implications for patient prognosis and treatment. E2F1, the most extensively studied member and the only one with prognostic value, exhibits a tumor-suppressing activity in esophageal, gastric and colorectal adenocarcinoma, and in hepatocellular carcinoma (HCC), whereas in pancreatic ductal adenocarcinoma and esophageal squamous cell carcinoma may function as a tumorpromoter. In the latter malignancies, E2F1 immunohistochemical expression has been correlated with higher tumor grade and worse patient survival, whereas in esophageal, gastric and colorectal adenocarcinomas is a marker of increased patient survival. E2F2 has only been studied in colorectal cancer, where its role is not considered significant. E2F4's role in colorectal, gastric and hepatic carcinogenesis is tumor-promoting. E2F8 is strongly upregulated in human HCC, thus possibly contributing to hepatocarcinogenesis. Adenoviral transfer of E2F as gene therapy to sensitize pancreatic cancer cells for chemotherapeutic agents has been used in experimental studies. Other therapeutic strategies are yet to be developed, but it appears that targeted approaches using E2F-agonists or antagonists should take into account the tissue-dependent function of each E2F member. Further understanding of E2Fs' contribution in cellular functions in vivo would help clarify their role in carcinogenesis.