Shift workers' body clocks studied to prevent certain cancers

Does shift work predispose you to cancer by altering the body's response to hormones?

And if so, can a dietary supplement help? Those are the questions researchers at The Cancer Institute of New Jersey (CINJ) hope to answer through a new study, which recently received $600,000 in funding from The V Foundation for Cancer Research. CINJ is a Center of Excellence of UMDNJ-Robert Wood Johnson Medical School.

The V Foundation Grant in Translational Clinical Research will support the work of the team led by Helmut Zarbl, PhD, ATS, associate director for Public Health Science at CINJ, and professor of toxicology at UMDNJ-Robert Wood Johnson Medical School, in the area of cancer prevention and circadian rhythms. Circadian rhythms are best described as one's “body clock,” which controls sleep, hunger, hormones, and activity among other things in all living cells.

According to Dr. Zarbl, epidemiological studies have consistently shown that women and men, who serve the community by working at night, have a significantly elevated risk of breast cancer and possibly prostate cancer. In fact, shift work that alters circadian rhythm is now classified as a probable carcinogen by the International Agency for Research Cancer. Zarbl and his team have recently found that chemical carcinogens also disrupt circadian rhythm, leading to what he considers an imbalance in a protein that prevents cancer by regulating the cell's response to hormones. More importantly, they found that a naturally occurring compound, methylselenocysteine (MSC), found in many foods, prevents cancer in rats by restoring circadian rhythm and the cell's response to estrogens. MSC contains the trace mineral selenium, which a number of epidemiological studies have shown can reduce the incidence of several types of cancer.

During the course of the three-year grant period, the team will determine if shift work also disrupts the cell's response to estrogens, and if this effect can be reversed by dietary MSC. The team will address these questions in two groups of participants. The first group comprised of primarily hospital workers will be asked to donate blood while working the day shift, and again after working at least one week on the night shift. This group will determine the effect of shift work on various biomarkers related to circadian rhythm and estrogen response.

In the second phase of the study, 100 volunteers who engage in traditional “shift work” professions, such as firefighters, police, airline and factory personnel, will be recruited through the New Jersey Family Medicine Research Network. For 30 days, this group will take an over-the-counter MSC supplement. Blood taken from these study participants will be used to determine if the MSC supplement can reverse the harmful effects of shift work on circadian rhythms and estrogen response. If so, the results will form the basis for a prospective study to determine if MSC supplements can prevent breast and prostate cancer in those who serve the community by working at night.

Zarbl, who also is the director of the NIEHS Center for Environmental Exposures and Disease at the Environmental & Occupational Health Sciences Institute (jointly administered by UMDNJ-Robert Wood Johnson Medical School and Rutgers, The State University of New Jersey), notes he is greatly appreciative of such support. “The V Foundation has long been committed to unlocking the mysteries of cancer through the funding of novel research. Through their generous support of this translational study, we have an opportunity to determine whether a supplementation of the diet with the amount of MSC found in a single Brazil nut can prevent two of the most common forms of cancer. The implications from such findings could be far reaching,” he noted.

“We're very excited about this project,” said Nick Valvano, CEO of The V Foundation for Cancer Research. “Through this important research, we're working toward a future where we can help people by preventing breast and prostate cancers.”

Co-investigators include Howard Kipen, MD, MPH, CINJ member and professor of environmental and occupational medicine at UMDNJ-Robert Wood Johnson Medical School; Benjamin Crabtree, PhD, co-program leader of the Population Science Program at CINJ and professor of epidemiology at UMDNJ-School of Public Health; and Pamela A. Ohman Strickland, PhD, who is an associate professor of biostatistics in the UMDNJ-School of Public Health. Mingzhu Fang, PhD, a senior staff scientist in the Zarbl laboratory and Terry Falco, who is the coordinator for the New Jersey Family Medicine Research Network, also are included on the team.

The award period runs through October 31, 2011.

About The Cancer Institute of New Jersey

The Cancer Institute of New Jersey (www.cinj.org) is the state's first and only National Cancer Institute-designated Comprehensive Cancer Center, and is dedicated to improving the prevention, detection, treatment and care of patients with cancer. CINJ's physician-scientists engage in translational research, transforming their laboratory discoveries into clinical practice quite literally bringing research to life. The Cancer Institute of New Jersey is a center of excellence of UMDNJ-Robert Wood Johnson Medical School. To support CINJ, please call the Cancer Institute of New Jersey Foundation at 1-888-333-CINJ.

The Cancer Institute of New Jersey Network is comprised of hospitals throughout the state and provides a mechanism to rapidly disseminate important discoveries into the community. Flagship Hospital: Robert Wood Johnson University Hospital. Affiliate Hospitals: Bayshore Community Hospital, Carol G. Simon Cancer Center at Morristown Memorial Hospital, Carol G. Simon Cancer Center at Overlook Hospital, CentraState Healthcare System, Cooper University Hospital*, Jersey Shore University Medical Center, JFK Medical Center, Raritan Bay Medical Center, Robert Wood Johnson University Hospital at Hamilton (CINJ at Hamilton), Saint Peter's University Hospital, Somerset Medical Center, Southern Ocean County Hospital, The University Hospital/UMDNJ-New Jersey Medical School*, and University Medical Center at Princeton. *Academic Affiliate