1Department of Obstetrics and Gynecology, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-Sen University, China
2Department of Neurology, The First Affiliated Hospital, Sun Yat-Sen University, China
Background and Aims: CRISPR/Cas9-mediated genome editing is a promising antiviral strategy, but its potential off-target effects greatly limit its clinical application. HPV infection is the key etiologic factor of cervical cancer. The aim was to use high specific SpCas9 variant and sgRNAs targeting the HPV 16 E6/E7 to eliminate HPV and reverse cancer.
Methods: We designed and screened efficient sgRNA to target HPV16 E6/E7 by T7E1. Cell apoptosis assay was used to compare the efficiency of inducing HPV type-specific apoptosis of different Cas9s. Moreover, we used GUIDE-seq technology to compare the on-target and off-target of SpCas9 and SpCas9-HF1. Importantly, we evaluated the effect of CRISPR reversing carcinogenesis by vaginal delivery of PBAE/SpCas9-HF1/HPV 16 E6-3 sgRNA nanoparticle targeting HPV16 E6 in K14-HPV transgenic mice.
Results: We identified that HPV 16 E6-3 sgRNA possesses the highest editing efficiency (34%), followed by HPV 16 E7-1 sgRNA (29.3%) when combined with SpCas9. Similar to SpCas9, SpCas9-HF1 can more effectively induce HPV positive cell apoptosis (27.6%) than eSpCas9 (21.3%). The off target of SpCas9-HF1 was significantly lower than SpCas9. Moreover, direct cervical application of PBAE/ SpCas9-HF1 nanoparticle targeting HPV16 E6 effectively is reversing the cervical lesions.
Conclusion: High fidelity CRISPR/Cas9 targeting HPV16 E6 could effectively cleavage HPV and lead to type-specific apoptosis of HPV-positive cells with low off-target effect. Importantly, direct delivery of PBAE/CRISPR nanoparticle targeting HPV16 E6/E7 directly to the cervix via the vagina is a safe and effective strategy for the treatment of HPV-related cervical lesions.
Rui Tian is a PhD student of the First Affiliated Hospital, Sun Yat-Sen University. Her work focuses specifically on (i) the mechanisms of HPV integration and its carcinogenic mechanism, and (ii) using different off-target assessment methods to select the most efficient and safe Cas proteins and sgRNAs to eliminate persistent HPV infection both in vitro and in vivo, thus paving the way for their therapeutic potential in the clinic. Her recent publication can be found in carcinogenesis journal.
1Oncology department, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, China
2Department of Medical Biochemistry and Microbiology, SciLifeLab Uppsala, The Biomedical Center, University of Uppsala, Sweden
3Department of Cell Biology, University of Uppsala, Sweden
4Cancer and Vascular Biology Research Center Rappaport, Faculty of Medicine, Israel
Heparanase expression has been found up-regulated in almost all types of lung cancers. To find out the implications of heparanase on lung cancer development, we examined the pathology of Lewis Lung Carcinoma (LLC2) cells growth after inoculation into the heparanase over expression mice (Hpa-tg) along with wild type (WT) control. Inoculation of the cells into the tail vein led to advanced lung colonization in the Hpa-tg mice. Injection of LLC2 cells into the right flank resulted in significantly faster growth and bigger tumors in the Hpa-tg mice, which were mainly, contributed by the higher proliferation of injected LLC2 cells. Higher proliferation of LLC2 cells, cultured in the conditioned medium of Hpa-MEF cells, indicates that stromal cells over expressing heparanase may release molecules stimulating LLC2 proliferation. This was further suggested by immuno-staining of enhanced Notch 1 signalling in the tumor. FACS analysis of the tumor-derived cells revealed fewer infiltrated neutrophils, but substantially higher percentage of IL-35+ cells in the Hpa-tg tumor. Further analysis of the cell population in the immune organs, spleen and inguinal lymph node revealed an overall suppressed immunity. Our findings suggest that heparanase expression in the host promoted LLC2 tumor growth through suppressing the anti-tumor immune response and the results support that application of heparanase inhibitors may strengthen the effects of current treatments for lung cancers.
Tahira Batool completed her PhD in Medical Biochemistry, Uppsala university, Sweden. She is a highly motivated biologist with 11 yearsʼ experience of studying and research in different branches of Biology. She has wide range of expertise in driving scientific projects with interdisciplinary background. She is presently looking for an opportunity to apply her skills and knowledge for the benefit of patients.
1Department of Obstetrics and Gynecology, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-Sen University, China
2Department of Neurology, The First Affiliated Hospital, Sun Yat-Sen University, China
Background: Zinc-finger nuclease (ZFN), transcription activator-like effector nuclease (TALEN) and clustered regulatory interspaced short palindromic repeat (CRISPR) RNA-guided nuclease are three types of programmable site-specific genome editing tools with a broad range of research and clinical applications. However, the knowledge of their effectiveness and genome-wide off-target cleavage activities has been lacking.
Methods: In this study, we chose three genes and designed three different sites for the same gene targeted by ZFN, TALEN and High-fidelity CRISPR (CRISPR-HF) separately. After evaluating the editing efficiency by T7E1 assay, we used the unbiased, genome-wide and sensitive DSB detection approach–-GUIDE-seq to compare their on-target and off-target profiles for total 9 different nucleases in SiHa cell line.
Results: The on-target efficiency of CRISPR-HFs was significantly higher than TALENs and ZFNs. Specifically, the average on-target efficiency of CRISPR-HF was 2.2-fold that of TALEN and 11.6-fold that of ZFN. Meanwhile, CRISPR-HFs induced less potential off-target cleavage sites (0, 1, 1, respectively) than TALENs (10, 13, 6, respectively) and ZFNs (9265, 2359, 247 respectively). However, the number of confident off-target positions was lowest in TALENs (0, 0, 0 respectively) followed by CRISPR-HFs (0, 1, 1 respectively) and ZFNs (1, 3, 0 respectively).
Conclusion: Our experiments suggest that CRISPR-HF outperformed ZFN and TALEN in cleavage efficiency and was not inferior to TALEN in off-target performance, which may serve as a promising choice in future genome-editing application.
Weiwen Fanis a PhD student. Presently working under the supervision of Zheng Hu (Doctoral Supervisor, Chief Special Scientist of the Ministry of Science and Technology, Young Top Talents in Ten-thousand Talents Program).
1Department of Gynecological oncology, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-Sen University, China
2Department of Neurology, First Affiliated Hospital, Sun Yat-Sen University, China
Background: Persistent high-risk HPV infection is recognized as the main factor of cervical cancer and HR-HPV oncogenes E6 and E7 play an important role in HPV carcinogenesis. Currently there is no effective treatment for HPV persistent infection. CRISPR/Cas9 system as one of the most promising genome-editing systems provided a powerful tool for the prevention and treatment of HPV infection. But effective and safe delivery of the CRISPR/Cas9 gene-editing elements remains a challenge.
Methods: A polyamide-amine (PAMAM)-poly(β-amino ester) hyperbranched copolymer (hPPC) was synthesized based on generation of PAMAM (PAMAM-G0) to deliver CRISPR/Cas9 system. We evaluated the transfection efficiency and cytotoxicity of hPPCs on HPV-positive cells (SiHa and HeLa) and SiHa ectopic xenografts nude mice model. Then we explored the growth inhibition of cervical cancer cells by using hPPC-CRISPR composite nanoparticles both invitro and invivo.
Results: We investigated the ability of hPPC to compress plasmid and the resultant polyplex NPs and evaluated the transfection efficiency and cytotoxicity of the system. Our hPPCs polyplex NPs showed low toxicity in cells and mouse organs. Both systems are tested in vitro and in vivo to evaluate their therapeutic potential. By reducing the expression of HPV16/18 E7, our hPPCs polyplex NPs could inhibit the growth of cervical cancer cells and xenograft tumors in nude mice.
Conclusion: hPPCs polyplex NP scan efficiently delivery CRISPR/Cas9 system, and HPV-targeting hPPCs polyplex NPs could potentially be developed as drugs to treat HPV infection and HPV-related cervical cancer.
Zhuang Jin is a PhD student, presently working under the supervision of Professor Zheng Hu (Doctoral Supervisor, Chief Special Scientist of the Ministry of Science and Technology, Young Top Talents in Ten-thousand Talents Program)
1Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, China
2Department of Neurology, The First Affiliated Hospital of Sun Yat-Sen University, China
Background: From initial HPV infection and precursor stages, the development of cervical cancer takes decades. High-sensitivity HPV DNA testing is currently recommended as primary screening method for cervical cancer, while better triage methodologies are encouraged to provide accurate risk management for HPV positive women.
Methods: Given that virus-driven genomic variation accumulates during cervical carcinogenesis, we designed a 39 Mb custom capture panel targeting 17 HPV types and 522 mutant genes related to cervical cancer. Using capture-based next-generation sequencing, HPV integration status, somatic mutation and copy number variation were analyzed on 34 paired samples, including 10 cases of HPV infection (HPV+), 10 cases of CIN1 and 14 cases of CIN2+ (CIN2: n=1; CIN2-3: n=3; CIN3: n=9; SCC: n=1). Finally, the Machine Learning Algorithm-Random Forest was applied to build the risk stratification model for cervical precursor lesions based on CIN2+ enriched biomarkers.
Results: Generally, HPV integration events (11 in HPV+, 25 in CIN1 and 56 in CIN2+), non-synonymous mutations (2 in CIN1, 12 in CIN2+) and copy number variations (19.1 in HPV+, 29.4 in CIN1 and 127 in CIN2+) increased from HPV+ to CIN2+. Interestingly, “common” deletion of mitochondrial chromosome was significantly observed in CIN2+ (P value=0.009). Together, CIN2+ enriched biomarkers, classified as HPV information, Mutation, Amplification, Deletion and mitochondrial change, successfully predicted CIN2+ with average accuracy probability score of 0.814, and Amplification and Deletion ranked as the most important features.
Conclusion: Our custom capture sequencing combined with machine learning method effectively stratified the risk of cervical lesions and provided valuable integrated triage strategies.
Zifeng Cui is a PhD student. Presently working under Professor Zheng Hu (Doctoral Supervisor, Chief Special Scientist of the Ministry of Science and Technology, Young Top Talents in Ten-thousand Talents Program)
Bezmialem Vakif University, Turkey
Introduction: Crohnʼs disease (CD) is a chronic intestinal disease. Biological agents are used for the remission induction and maintenance of remission in CD after the full investigation for tuberculosis according to the international guidelines. Here, we present a patient who developed “Active Pulmonary Tuberculosis (TB)” after the six months therapy with a biological agent (anti-TNF). After the anti-TB drugs treatment, control colonoscopy showed that patient is in remission. Mycobacterium organism appears as a one of the causes in the etiopathogenesis of crohnʼs patients.
Case: 22 year-old female patient was diagnosed as oderately active Crohnʼsileocholitis by biochemical, microbiological, colonoscopy, CT enterography and pathological examinations. At this time, intestinal biopsies and then tissue PCR and tissue tbc culture results did not reveal any evidence for tuberculosis. Azatiopurin (AZT) 2.5 mg / kg and oral Mesalazin were prescribed as ECCO guideline. After 4 months, because of no recovery, an anti-TNF was added. During this time, blood Quantiferon test was negative and the chest examination and chest X-ray were normal. Anti-TNF was started as protocol. She was in both clinical and laboratory remission at the 3rd and endoscopic remission at the 6th month of the therapy (both biologic and AZT). Then, she developed cough, sputum and night sweats. Pulmonary TB was detected by further examinations. The patient was a senior student in Turkey and living in a dormitory with two girlfriends. The height of the patient is 163 cm and her weight was measured as 46 kg during the first admission of hospital. Her last weight measurement was 53 kg before the diagnosis of TBC was made. There was no evidence of TB in her boyfriend and her room mates.
Discussion: Traditionally, immuno suppressants (IS; Azopirinand Methotrexate) are given in the treatment of Crohnʼs disease. Anti-TNF is started in patients with moderate or severe disease who have not responded to treatment after 4-6 months of IS. Since both of these regimens are immuno suppressive, before starting the anti-TNF therapy, Tuberculosis should be screened by 1) Quanti FERON-TB gold test, 2) Chest X-ray, 3) PPD test, and 4) all results and physical examination consulted by a chest diseases or infectious diseases physician. According to there commendations of Goverment, Republic of Turkey Ministry of Health, when the patient comes to each control, chest diseases spesialist have to examine the patient with chest X-ray and physical examination for the biologic approval. Although all the necessary precautions were taken according to the guidelines, a case of Pulmonary Tuberculosis developed after the 6 months of biologic plus immunosuppressive treatment was presented here to draw attention to this subject “tuberculosis infection and the unknown pathogenesis of Crohnʼs Disease”.
In conclusion, we would like to emphasize once again the role of mycobacterium strains in the unknown pathogenesis of crohnʼs patients.
Professor Basaranoglu Metin completed his postdoctoral studies in St. Louis University School of Medicine/Liver Centre, St. Louis/MO, USA. He is the author of a book: fatty liver pathogenesis (2009), and a book chapter (in Metabolic Aspects of Chronic Liver Diseases) published in NY (2008). He is a member of AASLD and EASL. He was awarded twice by AASLD (1998/2002) as a young investigator and once by EASL (2009).
Mohammad Rabiei-Faradonbeh3*, Mohammad-Taghi Moradi1 and Ali Karimi2
1Medical Plants Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Iran
2Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Iran
3School of Animal and Veterinary Sciences, The University of Adelaide, Australia
Objectives: High level of morbidity and mortality due to the influenza virus is an emerging public health concern. Because there are few approaches to control and treat this infection, plant extracts including pomegranate extract can be a treatment of choice. So, the present study was conducted to investigate the mechanism of action of PPE against influenza virus A/Puerto Rico/8/34 (H1N1; PR8) in MDCK cells.
Materials and Methods: In this research, a crude ethyl alcohol extract of pomegranate peel was prepared, and the action mechanism of PPE in inhibiting influenza replication was studied by time of addition assays, virucidal activity, RNA replication, hemagglutination inhibition assay, viral mRNA expression, and western blot analysis.
Results: Results showed that PPE inhibited viral polymerase activity, viral RNA replication, and viral protein expression but failed to influence hemagglutination inhibition and virucidal activity. According to the time of addition assay, PPE inhibited the virus adsorption and early step of influenza replication.
Conclusion: This study demonstrated that in vitro antiviral effect of PPE on the influenza virus is very likely to be associated with inhibition of viral adsorption and viral RNA transcription.
Keywords: Antiviral activity, Influenza virus, pomegranate, Punica granatum L.
Mohammad Rabiei-Faradonbeh first obtained an associate degree in Veterinary Medicine and then a Bachelor of Sciences degree in Veterinary Medical Laboratory Sciences. In 2013 he obtained a Master of Sciences degree in Medical Microbiology. More than 12 years working in laboratories has enabled me to develop and hone an excellent range of technical skills. Currently he funded by an Adelaide International Scholarship to obtain a PhD at the University of Adelaide. His project involves molecular pathology of newly emerged strains of Newcastle disease virus in Indonesia, which are a potential disease threat of great concern to Australiaʼs poultry industry
1School of Life Sciences, Gwangju Institute of Science and Technology, Republic of Korea
2Department of Internal Medicine, CHA Gangnam Medical Center, CHA University School of Medicine, Republic of Korea
3Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Republic of Korea
Chronic hepatitis B virus (HBV) infection can cause cirrhosis and hepatocellular carcinoma and is therefore a serious public health problem. Infected patients are currently treated with nucleoside/nucleotide analogs and interferon α, but this approach is not curative. Here, we screen 978 FDA-approved compounds for their ability to inhibit HBV replication in HBV-expressing HepG2.2.15 cells. We find that ciclopirox, a synthetic antifungal agent, strongly inhibits HBV replication in cells and in mice by blocking HBV capsid assembly. The crystal structure of the HBV core protein and ciclopirox complex reveals a unique binding mode at dimer-dimer interfaces. Ciclopirox synergizes with nucleoside/nucleotide analogs to prevent HBV replication in cells and in a humanized liver mouse model. Therefore, orally-administered ciclopirox may provide a novel opportunity to combat chronic HBV infection by blocking HBV capsid assembly.
Dr. Yoon-Jun Kim MD, PhD has been Professor of Internal Medicine at Seoul National University College of Medicine since 2013. While doing so, he remains active in the medical community through taking on leading roles in various professional societies such as Chair of the Academic Committee of The Korean Radio-Embolization Association, a position he has held since 2013, and from 2013 to 2014, he functioned as Chair of Academic Committee of The Korean Liver Cancer Study Group. Also, he served as secretary general of The Korean Liver Cancer Study Group from 2014 to 2015. Concurrently, he has been Editor-in-Chief of Clinical and Molecular Hepatology, a medical journal that publishes clinical and basic research on liver diseases, since 2015. His educational background began in the same college that he is now professor at, where he graduated from Seoul National University College of Medicine in 1992 and later went on to attain his Ph.D. there in 2001. Since graduating, his research interests in his particular field have included clinical studies of HBV infection and HCC, host genomics in HBV-related liver disease, clinical studies of NASH, cancer genomics of HCC, and basic studies of HCC pathogenesis.
Cornell University, USA
For over two decades now, plants have been explored for their potential to act as production platforms for biopharmaceuticals, such as vaccines and monoclonal antibodies. Without a doubt, the development of plant viruses as expression vectors for pharmaceutical production have played an integral role in the emergence of plants as inexpensive and facile systems for the generation of therapeutic proteins. More recently, plant viruses have been designed as non-toxic nanoparticles which can target a variety of cancers and thus empower the immune system to slow or even reverse tumor progression. The following presentation describes the employment of plant virus expression vectors for the treatment of some of the most challenging diseases known today. The presentation concludes with a projection of the multiple avenues by which virus nanoparticles could impact developing countries.
Kathleen Hefferon received her PhD from the Department of Medical Biophysics, University of Toronto and completed her postdoctoral fellowship at Cornell University. Kathleen has published multiple research papers, chapters and reviews, and has written three books. Kathleen is the Fulbright Canada Research Chair of Global Food Security and has been a visiting professor at the University of Toronto over the past year. Her research interests include virus expression vectors, food security agricultural biotechnology and global health. Kathleen lives in New York with her husband and two children.
1Department of Microbiology and Immunology, National Autonomous University of Mexico, Mexico
2Consejo Nacional de Ciencia y Tecnologia CONACyT – UAEH, Mexico
3Poultry Medicine Program, School of Veterinary Medicine, University of California, USA
Viral diseases are a constant threat to the poultry industry. The use of vaccines are one option to control/eradicate them. Different novel elements have been developed to improve the potency of vaccines. Chicken alpha interferon (CHIFN-α) is naturally produced by the immune system and has antiviral activity. It inhibits viral replication and protects uninfected cells. Thus, CHIFN-α could be a good candidate to improve the avian immune response against any viral disease. The use of genetic adjuvants will allow for a fast, low cost, and stable adjuvant production. In the present study, we evaluate the use of CHIFN-α as a genetic adjuvant in a nanoparticle format. The CHIFN-α sequence was codon optimized and cloned into an expression vector under the CMV promoter. DNA-chitosan nanoparticles were formed and combined with a commercial live vaccine against avian infectious bronchitis virus (IBV). SPF chickens were vaccinated and groups were immunized via the oculo-nasal route at 1 and 14 days of age and challenged 7 days after the last immunization with the M41 strain. Specific IgG and IgA antibody titers against IBV were measured by ELISA. Respiratory signs, viral load, tracheal histomorphometry, cilia score and quantification of CHIFN-α, IL-6, IL-10 and IL-1B were analyzed. These results will help evaluate the use of CHIFN-α as a genetic adjuvant in commercial chicken vaccines against IBV.
Dr. Jose A. Cano is an assistant professor working at UNAM, where he also previously received his DVM and PhD degree. He completed a postdoctoral position at the Biodesign Institute at Arizona State University (Dr. Stephen Johnstonʼs lab). He has held research positions in the pharmaceutical industry where he developed therapeutic monoclonal antibodies. He is currently a visiting Professor at UC Davis and is a member of the ASV. Currently, his research focuses on the generation of therapeutic biomolecules like avian and porcine interferons as well as the identification of epitope/mimotopes for the development of multiplex diagnosis methods.
Universidade Fernando Pessoa, Portugal
Rhinoviruses are picornavirus with over 150 serotypes and 3 species. Although usually causing common colds, in Asthma, COPD and elders it may cause life-threatening disease. Transmission routes are controversial, but may involve human-to-human and indirect transmission. Thus both environmental and genetic susceptibility factors may play a role in rhinovirus epidemiology.
In the present study we evaluated the seasonality of rhinovirus in Portugal and the role of air-borne virus, atmospheric parameters and Immune-system related genetic variations(TOLLIP rs5743899, IL6 rs1800795, IL1B rs16944, TNFA rs1800629).
Blood samples and monthly nasal swabs were collected from 89 volunteers.Weekly outdoor and indoor air samples were collected. Daily athmkospheric parameters were collected from the FP-ENAS meteorological station and the public air quality monitoring infrastructure. DNA and RNA were purified with Qiagen column based kits. Viral RNA was quantified by RTqPCR on Lightcycler 1.1 (Roche; 4). Polymorphisms were genotyped by PCR-RFLP.
Nasal Rhinovirus frequency peaked in November. No indoor-air samples showed rhinovirus. Outdoor air samples showed rhinovirus presence in concordance with the nasal samples. TOLLIP and IL6 polymorphisms (but not IL1B and TNF) were found to influence rhinovirus nasal detection: TOLLIP-G individuals were more often year-long rhinovirus free; IL6-C individuals showed higher rhinovirus titres. Wind Speed, Radiation, Atmospheric pressure, SO2, PM10, PM25 and benzene levels were found to influence the presence of nasal rhinovirus.
Conclusions: Air-borne rhinovirus correlates with human infection. This may be influenced by viral stability due to atmospheric conditions. Additionally, genetic factors influence both susceptibility to infection (TOLLIP gene) and viral clearance (IL6 gene).
José Cabeda has completed his PhD in 1996 from the University of Oporto. He was an assistant Professor at Universidade do porto from 1999-2001, has directed the Molecular Biology Diagnostic Unit of Centro Hospitalar do Porto (1999-2009), and has been CEO at Genefadi, a small Biotech company in Oporto. He is currently an Associated Professor at Universidade Fernando Pessoa, Porto, Portugal where he has been a teacher from 2001. He has published 36 papers in indexed journals, 4 book chapters and 2 books in the areas of molecular diagnostic and infection epidemiology.
Department of Pharmacy and Biotechnology, University of Bologna, Italy
Essential mechanisms at the basis of cancer are conserved across metazoans. In the last decades, the cancer community has developed several cellular and animal models that have greatly helped elucidate fundamental processes at work during cancer initiation and progression. In particular, the fruit fly Drosophila has been contributing relevant literature to the field. The conservation in the fruit fly of the genes and signalling pathways implicated in mammalian tumorigenesis and the availability of sophisticated systems favouring tailored genetic manipulation have made Drosophila a prominent model in cancer research. Despite obvious differences in organ anatomy, Drosophila studies have unveiled an amazing functional conservation of the physiology at the basis of organ development and maintenance. In parallel, dysfunction of key genes found deregulated in human cancers has been shown to promote tumour formation in the fly, fostering the development of humanised models bearing specific genetic alterations. I will present an overview of the manifold applications of Drosophila in cancer research, dwelling on some key findings from our lab illustrating how a biological phenomenon associated with cancer growth in the fruit fly can be profitably investigated in human cancers.
Daniela Grifoni is a geneticist and cell biologist who uses the fruit fly, Drosophila, to understand cancer, mainly focusing on the impact of MYC and cell competition on cancer initiation and progression. She obtained a PhD in Genetic Sciences at Ferrara University and a Specialty in Applied Genetics at University of Bologna. Daniela Grifoni is Adjunct Professor and Research Associate at the Department of Pharmacy and Biotechnology, University of Bologna, where she leads the CanceЯEvolutionLab (https://grifonilab.weebly.com).
Department of Thoracic Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, China
Objective: Previous studies have indicated that tumor length can impact the overall survival of esophageal squamous cell carcinoma (ESCC) patients. The aim of this study was to evaluate the cumulative incidence of death and to construct a model to predict the risk of cause-specific death for patients with ESCC by competing risk analysis.
Patients and methods: A total of 1650 ESCC patients who had undergone surgery between August 2000 and October 2012 in our hospital were retrospectively analyzed. In addition, 1681 samples retrieved from the SEER Program between 2010 and 2015 were defined as the external validation set. Cumulative incidence function (CIF) was calculated for mortality. The sub-distribution hazard model was developed to predict the risk of cause-specific death. The log-rank test and Cox regression analysis were also performed for survival analysis.
Results: Tumor size, age and lymph nodes involvement were significant factors for a high risk of cause-specific death as determined by competing risk analysis (all P<0.05). However, the sub-distribution model compared with traditional survival analysis resulted in a lower estimate of cause-specific mortality probability. According to the CIF, higher incidence rates of cause-specific death were observed among patients with tumor size ≥2.7 cm versus<2.7 cm (49.4% vs 35.0%). Similar results were also found in samples acquired from the SEER database.
Conclusions: We have developed a competing risk model to discuss cause-specific death for ESCC patients. A tumor size greater than 2.7 cm was found to be a prognostic indicator that is particularly associated with a higher risk of cancer-specific mortality.
Zhesheng Wen is the professor of oncology thoracic surgery in Sun Yat-Sen University Cancer Center and he masters the operating skill of various types of thoracic surgeries.