Epidemiologic and Translational Research in Digestive Diseases - Dr. Andrew Chan

Our research is focused on traditional, molecular, and genetic epidemiology of digestive diseases, including colorectal cancer, inflammatory bowel disease, and gastrointestinal bleeding.

We are affiliated with the Channing Laboratory, Epidemiology Section at Brigham and Women’s Hospital as well as the Harvard School of Public Health.  Through this affiliation, we actively participate in research using the Harvard epidemiological cohort studies, including the Nurses’ Health Study I, Nurses’ Health Study II, and Health Professionals Follow-up Study.  These cohorts provide unprecedented access to a range of longitudinally collected epidemiologic questionnaire data that are consistently updated over greater than 30 years of follow-up.  Within these cohorts, we have archived biospecimens of plasma, DNA, and tumor material for correlative science and translational research projects. 

Postdoctoral fellows/faculty
Ashwin Ananthakrishnan, MD, MPH
Manish Gala, MD
Hamed Khalili, MD, MPH
Lindsay King, MD
Gauree Konjieti, MD, MPH
Paul Lochhead, MBBS
Lily Maguire, MD
Reiko Nishihara, PhD

Doctoral students
Mingyang Song, MPH

Medical students
Raaj Mehta
Navya Bezawada 

Research assistants
Mustafa Atar, MD
Prakriti Kaini

Elaine Coughlan-Gifford

Administrative assistants
Mariane Leonard
Alisha Wilkinson


1. Epidemiology of colorectal adenoma and cancer. Our specific focus is on the prevention of colorectal adenoma and cancer using chemopreventative drugs and lifestyle interventions. Most recently, aspirin has emerged as promising agent for prevention of colorectal cancer. We have been conducting studies evaluating the optimal dose and duration of aspirin therapy, as well as defining potential populations that may preferentially benefit. We are also interested in genetic and biochemical markers that may be used to stratify risk of colorectal cancer for individuals, as well as predict responsiveness to various interventions.  This work is also being extended into using epidemiological methods to understand the role of inflammation in colorectal cancer risk and prognosis.

2. Genetic epidemiology of colorectal cancer.  We coordinate the Harvard cohorts in a national consortium of epidemiological studies of colorectal cancer which have assembled to conduct a large scale genome wide association study of colorectal cancer.  A principal aim of the consortium is to investigate the interaction between known environmental risk factors for colorectal cancer and genetic risk loci.

3. Molecular correlates of clinical outcomes in colorectal cancer.  With colleagues at the Fred Hutchinson Cancer Research Center and Mayo Clinic, we are currently conducting a genome wide association study of survival outcomes and therapy-related toxicity among several thousand patients with colorectal cancer enrolled in Phase III clinical trials.  

4. Epidemiology of gastrointestinal bleeding. Our specific focus is on lifestyle risk factors for gastrointestinal bleeding, including intake of medications such as aspirin and NSAIDs. We are also examining the influence of genetic and biomarker risk factors for gastrointestinal bleeding.

5. Molecular imaging of gastrointestinal neoplasia. In collaboration with biotechnology firms, we are working to clinically translate novel near infrared activatable agents that selectively target tumor-specific cathepsin proteases. We are interested in using these agents with fluorescent imaging endoscopy to enhance the detection of colorectal and esophageal neoplasia.

6.  Epidemiology of inflammatory bowel disease. Our specific focus is on lifestyle and dietary factors and risk of incident Crohn’s Disease and ulcerative colitis.  Based on this work, we will ultimately examine how these factors interact with known genetic risk loci for Crohn’s and ulcerative colitis.

Selected Peer-reviewed Publications

  1. Yamauchi M, Imamura Y, Willett WC, Rosner BR, Fuchs CS, Giovannucci E, Ogino S, Chan AT † (co-senior authors).  Long-term colorectal-cancer incidence and mortality after lower endoscopy.  N Engl J Med 2013. 369(12):1095-105. 
  2. Nishihara R, Lochhead P, Kuchiba A, Jung S, Yamauchi M, Liao X, Imamura Y, Qian ZR, Morikawa T, Wang M, Spiegelman D, Cho E, Giovannucci E, Fuchs CS, Chan AT, Ogino S † (co-senior authors).  Aspirin use and risk of colorectal cancer according to BRAF mutation status. JAMA. 2013. 309: 2563-71. PMCID: PMC3743040
  3. Liao X, Lochhead P, Nishihara R, Morikawa T, Kuchiba A, Yamauchi M,  Imamura Y, Qian Z, Baba Y, Shima K, Meyerhardt JA, Giovannucci E, Fuchs CS, Chan AT, Ogino S † (co-senior authors). Aspirin use, PIK3CA mutation, and colorectal cancer survival. N Engl J Med. 2012; 367: 1596-606.  PMCID: PMC3532946
  4. Chan AT, Ogino S, Giovannucci EL, Fuchs CS. Inflammatory markers are associated with risk of colorectal cancer and chemopreventative response to anti-inflammatory drugs. Gastroenterology. 2011.  140(3): 799-808. PMCID: PMC3049858
  5. Chan AT, Ogino S, Fuchs CS. Aspirin use and survival after diagnosis of colorectal cancer. JAMA. 2009;302(6):649-58. PMCID: PMC2848289. Chan AT, Ogino S, Fuchs CS. Aspirin and the risk of colorectal cancer in relation to the expression of COX-2. N Engl J Med. 2007;356(21):2131-42. 
  6. Chan AT, Giovannucci EL, Meyerhardt JA, Schernhammer ES, Curhan GC, Fuchs CS. Long-term use of aspirin and nonsteroidal anti-inflammatory drugs and risk of colorectal cancer. JAMA 2005. 294(8):914-923. PMCID: PMC1550973
  7. Phipps AI, Newcomb PA, Garcia-Albeniz X, Hutter CM, White E, Fuchs CS, Hazra A, Ogino S, Nan H, Ma J, Campbell PT, Figueiredo JC, Peters U, Chan AT. Association between colorectal cancer susceptibility loci and survival time following diagnosis with colorectal cancer. Gastroenterology 2012 July. 143(1): 51-54. PMCID: PMC3579620.
  8. Ananthakrishnan AN, Khalili H, Konijeti GG, Higuchi LM, de Silva P, Korzenik JR, Fuchs CS, Willett WC, Richter JM, Chan AT.  A prospective study of long-term intake of dietary fiber and risk of Crohn’s disease and ulcerative colitis.  Gastroenterology. 2013 Aug 1. 
  9. Ananthakrishnan AN, Khalili H, Konijeti GG, Higuchi LM, de Silva P, Fuchs CS, Willett WC, Richter JM, Chan AT.  Long-term intake of dietary fat and risk of ulcerative colitis and Crohn’s disease. Gut. 2013 Jul 4.
  10. Khalili H, Higuchi LM, Ananthakrishnan AN, Manson JE, Feskanich D, Richter JM, Fuchs CS, Chan AT.  Hormone therapy increases risk of ulcerative colitis but not Crohn's disease.  Gastroenterology. 2012. doi: 10.1053/gastro.2012.07.096. PMCID:PMC3480540.
  11. Khalili H, Huang ES, Ananthakrishan AN, Higuchi L, Richter JM, Fuchs CS, Chan AT. Geographical variation and the risk of inflammatory bowel disease among U.S. women. Gut 2012 Jan 11. PMCID: PMC3418414.
  12. Ananthakrishan AN, Khalili H, Higuchi LM, Bao Y, Korzenik JR, Giovannucci EL, Richter JM, Fuchs CS, Chan AT. Higher predicted vitamin D status is associated with reduced risk of Crohn's disease. Gastroenterology 2012; 142(3): 482-9. PMCID: PMC3367959.
  13. Ananthakrishan AN, Higuchi LM, Huang ES, Khalili H, Richter JM, Fuchs CS, Chan AT. Aspirin, nonsteroidal anti-inflammatory drugs, and risk for Crohn disease and ulcerative colitis: a cohort study. Ann Internal Med 2012; 156 (5): 350-59. PMCID: PMC3369539.
  14. Khalili H, Higuchi L, Ananthakrishnan AN, Feskanich D, Richter JR, Fuchs CS, Chan AT. Oral contraceptives, reproductive factors and risk of inflammatory bowel disease. Gut 2012 May 22. PMCID: PMC3465475.
  15. Strate LL, Liu YL, Huang ES, Giovannucci EL, Chan AT. Use of aspirin and nonsteroidal anti-inflammatory drugs increases risk of diverticulitis and diverticular bleeding. Gastroenterology. 2011; 140: 1427-1433. PMCID: PMC3081980.