Infectious Agents and Cancer


Overview

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Is a Comprehensive Approach Necessary for Preventing Cancers Caused by Infectious Agents?
10/9/12



Figure: A pie chart illustrating how the Hepatitis B and C viruses, Human papillomavirus, and <em>Helicobacter pylori</em> make up a very large percentage of the infections in 2008 that lead to cancer incidence, compared to others such as the Epstein-Barr virus, Human herpes virus type 8, Human T-cell lymphotropic virus type 1, <em>Opisthorchis viverrini</em>, <em>Clonorchis sinensis</em>, and <em>Schistosoma haematobium</em>. This graph was made using data from <em>Lancet Oncology</em>, Volume 13, Issue 5, May 2012.

World Cancer Incidence Attributed to Infections in 2008
Click to enlarge.

The World Health Organization estimates about 2 million cancer cases per year (18% of the global cancer burden) are attributable to chronic infections cancer, making them the second most preventable cause of cancer. This prevalence is significantly larger in low- and -middle income countries (26%) than in high-income countries (8%). Thus prevention or eradication of these infections is pivotal to overcome inequalities in cancer incidence and reduce the global burden of infection-related cancers.

Interestingly, although many of these infections are highly prevalent in the world, most infected individuals do not develop cancer but remain lifelong carriers. Malignancies associated with infectious agents often occur after prolonged latency or chronic infections in the host.

The International Agency for Research on Cancer (IARC) has identified seven major infectious agents as carcinogenic to humans:

  • Hepatitis B virus (HBV),
  • Hepatitis C virus (HCV),
  • Certain strains of the human papilloma virus (HPV),
  • Epstein-Barr virus (EBV),
  • Human immunodeficiency virus type 1 (HIV-1),
  • Human T-cell lymphotropic virus type-1 (HTLV-1), and
  • Gram-negative bacterium Helicobacter pylori (H. pylori).

Despite several advances highlighting the role of infectious agents in cancer, the global burden of infection-related cancer is still high and in need of additional cancer surveillance, prevention, and treatment research. The presence of an infection is not sufficient to cause cancer and requires other cofactors in the host - such as genetic susceptibility, age, the robustness of the immune system, dietary habits, co-infections, and environmental factors. Co-infections, including HIV infection, alter the immune system, can increase host susceptibility to cancer, and are a leading cause of morbidity and mortality in some populations.

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Research Priorities

NCI's Epidemiology and Genomics Research Program (EGRP) supports various projects to develop resources and technologies for identifying key determinants of cancer risks and improving outcomes to reduce the cancer burden by:

  • Fostering domestic and international collaborative research through epidemiological studies to identify risk factors and biomarkers in high-risk populations who have infection-related cancers;
  • Understanding the natural history of infectious agents in causing cancer in diverse populations, investigating determinants of cancer incidence patterns, and identifying the pathogenic, host, or other factors that predispose some infected individuals to develop cancer;
  • Developing and improving epigenetics tools that can be used to identify sites of integration and targeted therapies for cancer prevention since many malignant viral infections are associated with integration of viral oncogenes into host DNA; and
  • Increase the understanding of the human microbiome to improve prevention and treatment of the coevolved infection.

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Funding Opportunities

NCI-sponsored Funding Opportunity Announcements (FOAs) related to infectious diseases and risk of cancer include:

  • Research on Malignancies in the Context of HIV/AIDS - expires September 8, 2016 unless reissued
  • Pilot Studies in Pancreatic Cancer - expires January 8, 2015 unless reissued
  • View the full list of EGRP FOAs

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Funded Projects

View a list of active infectious disease-related grants supported by the Epidemiology and Genomics Research Program (EGRP) in NCI's Division of Cancer Control and Population SciencesExternal Web Site Policy.

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Research Resources

  • AIDS and Cancer Specimen ResourceExternal Web Site Policy
    A collection of tissues and biological fluids with associated clinical and follow-up data from patients with HIV-related malignancies. Specimens and clinical data are available for research studies, particularly those that translate basic research findings to clinical application.
  • Center for AIDS Research (CFAR) Network of Integrated Clinical SystemsExternal Web Site Policy
    Provides integrated clinical data from the large and diverse population of HIV-infected people in the modern HIV/AIDS Alliance for Region Two (HAART) era who are receiving care at one of the many U.S. federally funded CFAR sites and data to address the challenging and rapidly evolving issues in HIV care and research.
  • National Institute of Allergy and Infectious Diseases (NIAID) Research ResourcesExternal Web Site Policy
    A compilation of scientific literature, laboratory and clinical research support and tools, and training opportunities.
  • NIH Common Fund Human Microbiome ProjectExternal Web Site Policy
    Provides links to funding opportunities and research resources enabling comprehensive characterization of the human microbiota and analysis of their role in human health and disease.

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Public Resources

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Selected Publications

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Contacts

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