Lisa Martin, Ph.D.
Assistant Professor
Departments of Medical Biophysics and Nutritional Sciences Scientist

Ph: 416.946.2339
Fax: 416.946.2024
lmartin@uhnresearch.ca




Primary Affiliations:

• Departments of Medical Biophysics and Nutritional Sciences Scientist,
  Applied Molecular Oncology Ontario Cancer Institute

Research:

Etiology and Prevention of Breast Cancer

 




• Our research focuses on the etiology and prevention of breast cancer with an emphasis on mammographic density.  Mammographic density refers to a pattern of breast tissue composition (as seen on a mammogram) that is strongly associated with the risk of developing breast cancer, is common in the population, and is highly heritable. An understanding of the etiology of mammographic density, and how it is related to breast cancer risk, is likely to lead to effective preventative interventions for breast cancer.  Our research uses an epidemiological approach that includes the study of diet and lifestyle factors, as well as biochemical, genetic and molecular factors measured in a variety of biological samples.
  
  
• We have recently completed a long-term, multi-centre clinical trial to determine if a low-fat diet will reduce the incidence of breast cancer in women with extensive mammographic density (in collaboration with Dr. Boyd, Principal Investigator).  The analysis of the data from this trial is currently underway.  Future work will include an examination of the effects of diet on mammographic density, blood hormones and growth factors as well as breast tumour characteristics.
  
  
• Additional studies are investigating the relationship of mammographic density with markers of oxidative stress/inflammation and with blood telomere length. We have previously shown that increased urinary malondialdehyde, a marker of lipid peroxidation, is associated with increased mammographic density. We will extend this observation by studying more specific measures of lipid peroxidation (eg. urinary isoprostanes) and markers of inflammation produced from arachidonic acid via the COX-2 pathway (eg. urinary prostaglandin E2).
  
  
• Telomeres, which cap the ends of chromosomes and promote their stability, become shorter with cell replication and exposure to oxidative stress. Shorter blood telomere length has been associated with higher risk of some types of cancer.  Currently we are examining whether blood telomere length is associated with mammographic density and other risk factors for breast cancer. We have set up a quantitative PCR technique to facilitate measurement of blood telomere length in large epidemiological studies, This work may suggest a novel way in which mammographic density is related to breast cancer and motivate future studies to examine whether blood telomere length is a marker of breast cancer risk.

Selected Publications:                                                   

• Martin LJ, and Boyd NF. Potential mechanisms of breast cancer risk associated with mammographic density: hypotheses based on epidemiological evidence.  Breast Cancer Research.  Accepted November 2007.
  
  
• Boyd NF, Guo H, Martin LJ, Sun L, Stone J, Fishell E, Jong R, Hislop G, Chiarelli A, Minkin S, Yaffe M.  Mammographic density, and risk and detection of breast cancer in screened populations. 
  N Eng J Med.  356:11-20, 2007.
  
  
• Boyd NF, Martin LJ, Sun L, Guo H, Chiarelli A, Hislop G, Yaffe M, Minkin S.  Body size, mammographic density and breast cancer risk.  Cancer Epidemiol Biomarkers Prev. 15:2086-2092, 2006.
  
  
• Martin LJ, Greenberg C, Kriukov V, Minkin S, Jenkins DJA, Boyd N.  Intervention with a low-fat, high carbohydrate diet does not influence the timing of menopause. Am J Clin Nutr. 84:920-928. 2006
  
  PubMed