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Cynthia L Sears, M.D.

Photo of Dr. Cynthia L Sears, M.D.

Professor of Medicine


Expertise: Diarrheal Disease, Infectious Disease, Infectious Diseases

Research Interests: Infectious diarrheal diseases; cryptosporidiosis; food borne disease; bacteroides fragilis infections

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The Johns Hopkins Hospital (Main Entrance)


1800 Orleans St. Sheikh Zayed Tower Baltimore, MD 21287 map


Dr. Cynthia Sears is a professor of medicine at the Johns Hopkins University School of Medicine and a member of the Johns Hopkins Kimmel Cancer Center as well as a member of The Bloomberg~Kimmel Institute for Cancer Immunotherapy. Her laboratory focuses on the pathogenesis of colon disease by enteric bacteria using enterotoxigenic Bacteroides fragilis (ETBF) as a model for inducing colon inflammation. Her lab identified the B. fragilis toxin gene (bft), purified the protein (BFT) and defined its mechanism of action in vitro. More recently, her team established in vivo models of ETBF colitis and colon tumorigenesis. Using these models, her team identified that ETBF induce selective Stat3/Th17 immune responses in the colon and that these pathways, at least in part, contribute to colon tumorigenesis. Her lab was the first to report this mechanism for inflammation-induced endogenous colon tumor induction in response to colon colonization with a human commensal (up to 40 percent of ETBF-colonized humans are asymptomatic). Her team is extending this work to human studies to understand the microbial contribution to colitis and colon cancer pathogenesis. Studies in her laboratory include the molecular mechanisms by which BFT and ETBF induce colon carcinogenesis, including identifying the BFT receptor, defining BFT-induced activation of colonic epithelial signaling pathways, determining the immunologic  determinants of colon carcinogenesis and establishing the genetic and epigenetic mutations contributing to colon tumor induction and promotion stimulated by ETBF through BFT. more


  • Professor of Medicine
  • Professor of Oncology

Departments / Divisions



  • MD, Sidney Kimmel Medical College of Thomas Jefferson University (1977)

Board Certifications

  • American Board of Internal Medicine / Infectious Disease (1986)
  • American Board of Internal Medicine / Internal Medicine (1980)

Research & Publications

Research Summary

Expert in foodborne and enteric infections and has studied the pathogenesis of enterotoxigenic Bacteroides fragilis (ETBF) both in the laboratory and in clinical settings over the past nearly 20 years.  Scientific work has been funded continuously by the NIH since 1993.  Presently focusing on mouse and human studies to define how ETBF and the colonic microbiota induce chronie colonic inflammation and colon cancer.

Contact for Research Inquiries

Johns Hopkins University
1550 Orleans Street
Suite 1M05
Baltimore, MD 21287 map

Activities & Honors

Professional Activities

  • Associate Editor, Clinical Infectious Deiseases, 2000
  • President, Anaerobe Society of the Americas

Videos & Media

Recent News Articles and Media Coverage

Biofilm Holds Clues to Colon Cancer, Inside Tract (Summer, 2016)

Patient Ratings & Comments

The Patient Rating score is an average of all responses to physician related questions on the national CG-CAHPS Medical Practice patient experience survey through Press Ganey. Responses are measured on a scale of 1 to 5, with 5 being the best score. Comments are also gathered from our CG-CAHPS Medical Practice Survey through Press Ganey and displayed in their entirety. Patients are de-identified for confidentiality and patient privacy.

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