What do colorectal cancer and HIV have in common? They were both topics of winning posters at the 16th Annual Poster and Exhibit Day held in the Kresge cafeteria on February 28.

More than 50 people or groups presented posters or exhibits. Those prepared by students or by a team on which a student was the first author and presenter were eligible for a $500 prize, as judged by the Faculty Council. The Council chose two winners this year:

Eva Schernhammer, Department of Epidemiology

"Rotating Night Shifts and Risk of Colorectal Cancer in Women Participating in the Nurses’ Health Study"

Last October, Eva Schernhammer published a paper in the Journal of the National Cancer Institute indicating that women who work night shifts over the course of years may have an increased risk for developing breast cancer. The reason why could have to do with the hormone melatonin, which helps to regulate sleep/wake cycles. Decreased levels of the hormone may promote tumor growth or affect levels of other hormones in the bloodstream, such as estrogen. Melatonin production peaks at night but drops off dramatically when people are exposed to light.

Now, Schernhammer is looking into the possibility of a similar link between night-shift work and colorectal cancer. Using the Nurses’ Health Study, she has found that women who worked for more than 15 years on rotating night shifts had a greater risk of colorectal cancer by more than 35 percent than people who did not work at night. The women at greater risk worked at least three nights per month.

Schernhammer is currently writing a paper based on her findings and said that the results need to be confirmed in other studies. She added that investigation of the role of melatonin in cancer risk should be further explored.

"There were so many great posters that I was surprised when I heard that I had won," said Schernhammer.

Seema Thakore, Department of Immunology and Infectious Diseases

"A Novel HIV-1 Sub-subtype from West Africa"

Seema Thakore (standing to left in photo) is characterizing a newly recognized form of HIV discovered in a group of commercial sex workers in Senegal.

The "sub-subtype" is tentatively called A3.

Thakore is analyzing the DNA of HIV taken from cells of the workers and comparing the sequences to known forms of HIV to spot differences and similarities. After understanding the structural specifics of A3, Thakore aims to study other aspects of the sub-subtype, such as the rate at which A3 progresses to AIDS.

"It’s an honor to have been one of the winners, and it really encourages me to continue working on this research," said Thakore.

Honorable mentions went to: Pauline Koh-Banerjee of the Department of Nutrition; Uwe Siebert of the Harvard Center for Risk Analysis and the Departments of Epidemiology and Health Policy and Management; Judy Tsai of the Department of Nutrition; and Lisa Wang of the Departments of Epidemiology and Environmental Health.

The winning posters are on display in a case in the hallway connecting the Kresge Building to Building I.