Publications by authors named "Abedi-Ardekani B"

Colorectal cancer incidence rates vary geographically and have changed over time. Notably, in the past two decades, the incidence of early-onset colorectal cancer, affecting individuals under the age of 50 years, has doubled in many countries. The reasons for this increase are unknown.

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Various terms are used to describe non-malignant tissue located in the proximity of a tumor, belonging to the organ from which the tumor originated. Traditionally, these tissues, sometimes called "normal adjacent tissue" have been used as controls in cancer studies, and were considered representative of morphologically healthy, non-cancerous tissue. However, with the advancement of OMIC technologies, such tissues are increasingly recognized to be distinct from both tumor and healthy tissues.

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  • Next-generation sequencing techniques, like whole-exome and error-corrected sequencing, are used to analyze mutation patterns in both cancerous and non-cancerous tissues.
  • The review emphasizes the potential of using these techniques on archived tissue samples fixed in formalin or alcohol to identify mutational signatures that reflect prior exposure to mutagens.
  • By distinguishing between DNA damage from tissue fixation and true biological mutations, this research helps improve our understanding of cancer causes and supports prevention strategies aimed at reducing exposure to cancer risk agents.
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Tobacco smoke, alone or combined with alcohol, is the predominant cause of head and neck cancer (HNC). Here, we further explore how tobacco exposure contributes to cancer development by mutational signature analysis of 265 whole-genome sequenced HNC from eight countries. Six tobacco-associated mutational signatures were detected, including some not previously reported.

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International differences in the incidence of many cancer types indicate the existence of carcinogen exposures that have not yet been identified by conventional epidemiology make a substantial contribution to cancer burden. In clear cell renal cell carcinoma, obesity, hypertension and tobacco smoking are risk factors, but they do not explain the geographical variation in its incidence. Underlying causes can be inferred by sequencing the genomes of cancers from populations with different incidence rates and detecting differences in patterns of somatic mutations.

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Here, in a multi-ancestry genome-wide association study meta-analysis of kidney cancer (29,020 cases and 835,670 controls), we identified 63 susceptibility regions (50 novel) containing 108 independent risk loci. In analyses stratified by subtype, 52 regions (78 loci) were associated with clear cell renal cell carcinoma (RCC) and 6 regions (7 loci) with papillary RCC. Notably, we report a variant common in African ancestry individuals ( rs7629500 ) in the 3' untranslated region of VHL, nearly tripling clear cell RCC risk (odds ratio 2.

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Large-scale biorepositories and databases are essential to generate equitable, effective, and sustainable advances in cancer prevention, early detection, cancer therapy, cancer care, and surveillance. The Mutographs project has created a large genomic dataset and biorepository of over 7,800 cancer cases from 30 countries across five continents with extensive demographic, lifestyle, environmental, and clinical information. Whole-genome sequencing is being finalized for over 4,000 cases, with the primary goal of understanding the causes of cancer at eight anatomic sites.

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Background: Multiple primary cancers (MPC) present many coding difficulties, while a distinction should be made between new cases and those with metastasis and/or extension and recurrence of the primary ones. We aimed to reflect on the experiences and results of data quality control of the East Azerbaijan/Iran Population-Based Cancer Registry and present our suggested rules for reporting, recording and registering multiple primary cancer.

Methods: Comparability, validity, timeliness, and completeness of data assessment were performed.

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Article Synopsis
  • A study investigated the role of tumor genomics in predicting recurrence risk for patients with localized clear-cell renal cell carcinoma (ccRCC) after surgery, using a large cohort of 943 cases.
  • Researchers analyzed the mutation status of 12 genes, particularly focusing on von-Hippel Lindau (VHL) mutations, finding distinct groups with different disease-free survival rates.
  • The results suggest that genomic profiling can help tailor adjuvant treatment decisions, with patients having only a VHL mutation possibly needing less aggressive therapy compared to those with additional mutations.
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  • Gastric cancer (GC) and oesophageal cancer (EC) have distinct epidemiological profiles, and their incidence rates and trends vary globally by subtype.
  • Data from population-based cancer registries showed that the ratio of GC to EC incidence differs significantly across regions, with GC being more prevalent in certain South American and Asian countries, while EC is predominant in sub-Saharan Africa.
  • Over the years 1998 to 2012, GC rates have generally decreased by 2%-3% annually, whereas EC trends vary by subtype, with increases in certain types like esophageal adenocarcinoma (EAC) and decreases in others like esophageal squamous cell carcinoma (ESCC).
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  • Esophageal squamous cell carcinoma (ESCC) is more common in certain areas of Africa and Asia, with new research suggesting a link between poor oral health and ESCC.
  • An analysis of tumor samples from ESCC patients has identified specific bacteria, such as Fusobacterium and Prevotella, present in higher amounts in tumors from various high-incidence regions.
  • The study also found that the microbiomes of saliva and tumors in ESCC patients were similar, indicating that oral bacteria may contribute to the development of ESCC.
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Background: Consumption of very-hot beverages/food is a probable carcinogen. In East Africa, we investigated esophageal squamous cell carcinoma (ESCC) risk in relation to four thermal exposure metrics separately and in a combined score.

Methods: From the ESCCAPE case-control studies in Blantyre, Malawi (2017-20) and Kilimanjaro, Tanzania (2015-19), we used logistic regression models adjusted for country, age, sex, alcohol and tobacco, to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for self-reported thermal exposures whilst consuming tea, coffee and/or porridge.

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  • This study investigates genetic factors influencing lung cancer (LC) susceptibility by analyzing data from a large sample of patients and controls, combining findings from two major genome-wide association studies (GWAS).
  • The analysis identified eight new genetic loci associated with lung cancer, implicating genes related to DNA repair, metabolism, and smoking behaviors, which are crucial for understanding genetic risk.
  • Results from polygenic risk score (PRS) analysis suggest that higher genetic loads of smoking-related variants are linked to increased mutation burdens in lung tumors, providing insights into how genetic variations contribute to lung cancer development.
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Background: Little is known about how factors combine to influence progression of squamous cell carcinoma of the head and neck (HNSCC). We aimed to evaluate multidimensional influences of factors associated with HNSCC stage by race.

Methods: Using retrospective data, patients with similar socioeconomic status (SES), access to care (travel time/distance), and behavioral risk factors (tobacco/alcohol use and dental care) were grouped by latent class analysis.

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Esophageal squamous cell carcinoma (ESCC) shows remarkable variation in incidence that is not fully explained by known lifestyle and environmental risk factors. It has been speculated that an unknown exogenous exposure(s) could be responsible. Here we combine the fields of mutational signature analysis with cancer epidemiology to study 552 ESCC genomes from eight countries with varying incidence rates.

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Background: We aim to present the development and the initial results of the Golestan Cancer Biobank (GoCB), in a low resource setting in northern Iran.

Methods: The GoCB protocol and its standard operation procedures (SOP) were developed according to internationally accepted standards and protocols with some modifications considering the limited resources in our setting. The main biological samples collected by the GoCB include blood sample, urine sample, fresh endoscopy tissue sample, fresh surgical tissue sample and formalin fixed paraffin embedded (FFPE) tissue sample.

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Circulating cell-free DNA (cfDNA) is emerging as a potential tumor biomarker. CfDNA-based biomarkers may be applicable in tumors without an available non-invasive screening method among at-risk populations. Esophageal squamous cell carcinoma (ESCC) and residents of the Asian cancer belt are examples of those malignancies and populations.

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  • * A significant number of differentially methylated positions (6,796) and regions (866) were identified, indicating that tumor cells exhibited a notable increase in hypermethylation, particularly in gene promoter and body regions.
  • * The research highlights three key genes with consistent methylation differences that could serve as potential biomarkers for ESCC, suggesting that these findings could lead to further exploration of DNA methylation's role in cancer diagnosis and treatment.
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  • A study examined the link between long-term opiate use and cardiovascular mortality among 50,045 Iranian participants aged 40-75, finding that users had significantly higher death rates from cardiovascular issues compared to non-users.
  • Opiate users in the study had a median usage of 10 years, and out of 548,940 person-years, there were 3,079 cardiovascular deaths, revealing that 10.9% of these deaths were attributed to opiate use.
  • The research concluded that long-term opiate use is linked to increased cardiovascular mortality independent of traditional risk factors, suggesting the need for further investigation into the underlying mechanisms.
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Sexual dimorphism in cancer incidence and outcome is widespread. Understanding the underlying mechanisms is fundamental to improve cancer prevention and clinical management. Sex disparities are particularly striking in kidney cancer: across diverse populations, men consistently show unexplained 2-fold increased incidence and worse prognosis.

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There are unexplained geographical variations in the incidence of kidney cancer with the high rates reported in Baltic countries, as well as eastern and central Europe. Having access to a large and well-annotated collection of "tumor/non-tumor" pairs of kidney cancer patients from the Czech Republic, Romania, Serbia, UK, and Russia, we aimed to analyze the morphology of non-neoplastic renal tissue in nephrectomy specimens. By applying digital pathology, we performed a microscopic examination of 1012 frozen non-neoplastic kidney tissues from patients with renal cell carcinoma.

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In the African esophageal squamous cell carcinoma (ESCC) corridor, recent work from Kenya found increased ESCC risk associated with poor oral health, including an ill-understood association with dental fluorosis. We examined these associations in a Tanzanian study, which included examination of potential biases influencing the latter association. This age and sex frequency-matched case-control study included 310 ESCC cases and 313 hospital visitor/patient controls.

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  • The study investigates racial disparities in overall survival rates for patients with HPV-associated oropharyngeal squamous cell carcinoma (OPSCC), focusing on differences between black and white patients.
  • It found that black patients were typically younger, had lower incomes, lived farther from treatment centers, and presented with more advanced cancer stages, contributing to worse survival outcomes.
  • Despite adjusting for various demographic, clinical, and socioeconomic factors, racial disparities in survival persisted, with black patients still facing significantly higher risks of mortality from the disease.
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Esophageal sponge cytology is an endoscopy alternative well accepted by patients with extensive data for accuracy in the context of adenocarcinoma. Few studies have assessed its feasibility in asymptomatic community members, and fewer still in East Africa, where esophageal squamous cell carcinoma (ESCC) rates are high. We aimed to assess the feasibility of a capsule-based diagnosis of esophageal squamous dysplasia (ESD), an ESCC precursor, which may benefit epidemiological and early detection research.

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Background: Breast cancer is the second leading cause of death from cancer in women in sub-Saharan Africa, yet there are few well characterised large-scale survival studies with complete follow-up data. We aimed to provide robust survival estimates in women in this setting and apportion the survival gaps.

Methods: The African Breast Cancer-Disparities in Outcomes (ABC-DO) prospective cohort study was done at eight hospitals across five sub-Saharan African countries (Namibia, Nigeria, South Africa, Uganda, and Zambia).

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