Dr. Serena Houghton, a postdoctoral researcher in and alumna of the department of biostatistics and epidemiology at the University of Massachusetts Amherst School of Public Health and Health Sciences, has received a three-year, $187,639 Ruth L. Kirschstein National Research Service Award Individual Postdoctoral Fellowship from the National Cancer Institute to examine central obesity and its relation to breast cancer risk and survival.
Dr. Houghton works under the supervision of UMass-Amherst professor of epidemiology Dr. Susan Hankinson, an internationally renowned breast cancer researcher. Notes Dr. Hankinson, “Serena developed strong skills in epidemiology and biostatistics as a doctoral student here at UMass – and she has only recently transitioned to concentrate on cancer epidemiology. She has shown herself to be smart, thoughtful and committed to applying her knowledge to better understand causes and ways to prevent cancer. That she obtained this prestigious NIH fellowship on her first submission speaks volumes to her work and her potential.”
Dr. Houghton’s study aims to evaluate whether central obesity (e.g., waist circumference) is a better predictor of breast cancer risk and survival than general obesity measures, such as body mass index (BMI). Additionally, she will assess specific tumor markers to help confirm whether central obesity causes breast cancer and, if so, how. The results may suggest new ways to identify women who are at high risk of breast cancer, and who may benefit from increased screening or additional strategies to prevent breast cancer.
BMI has been well established as a risk factor that is inversely related to premenopausal breast cancer and positively associated with postmenopausal breast cancer. In contrast, central obesity, as measured by waist circumference or waist-to-hip ratio, is characterized by high levels of metabolically active visceral fat that leads to alterations in multiple hormones (e.g., insulin), inflammatory cytokines, and adipokines, all of which have been implicated in breast cancer development.
Dr. Houghton hypothesizes that measures of central obesity will provide further indications about breast cancer risk and survival than BMI alone. To date, few studies have evaluated the link with premenopausal breast cancers and even fewer have evaluated associations according to important tumor characteristics and molecular subtypes. Dr. Houghton will examine the independent association of central obesity with breast cancer risk by menopausal status; the relationship by tumor molecular subtypes and by several key tumor characteristics (i.e., estrogen receptor, androgen receptor, insulin receptor expression, PTEN loss, PIK3CA mutations); and the association between central obesity and breast cancer survival.
To address these project aims, Dr. Houghton will analyze questionnaire and biospecimen data on the nearly 200,000 women enrolled in the Harvard Nurses Health Study (NHS) and NHS2, of whom 7,500 have been diagnosed with breast cancer. With a large number of premenopausal breast cancer cases, multiple waist measurements, long follow-up, and detailed tumor data, she hopes to improve understanding of central obesity’s role in breast carcinogenesis.
“By evaluating subtypes and tumor characteristics, I should gain substantial new insight into biological mechanisms and help confirm causality,” Dr. Houghton says. “This will allow us to identify women at higher risk for breast cancer development and lower risk of breast cancer survival. The results gained from this work may improve risk prediction models to help identify women at high risk of developing breast cancer. These women may be potential candidates for chemoprevention or other risk-reducing options, such as increased physical activity.”
Adds Dr. Houghton, “Given the substantial morbidity and mortality associated with a diagnosis of breast cancer, the identification of modifiable risk factors and women at high risk for breast cancer is imperative.”
[Photo: Dr. Serena Houghton]