Thousands of people attending Relay For Life events this year will have a chance to do more than raise awareness and money for cancer research: They'll be able to enroll in an important new study that promises to shed light on many of the factors that influence how cancer develops and why.

The American Cancer Society is recruiting 500,000 people to take part in a long-term study of lifestyle and cancer called the Cancer Prevention Study-3, or CPS-3 for short. Participants will answer periodic questionnaires about their habits (what they eat, how much exercise they get, whether they smoke, etc.). Over the course of 20 years, the ACS researchers will follow the participants to see which ones develop cancer, in hopes of learning how a person's lifestyle, environment, and genetic makeup influence who gets the disease.

"While science can do a lot to explain the biology and genetics of cancer, some of the most valuable information we have is a direct result of the contributions of dedicated individuals over several generations," says study leader Eugenia Calle, PhD, managing director of analytic epidemiology at ACS.

Anyone between the ages of 30 and 65 who has never had cancer (other than basal or squamous cell skin cancer) can sign up for the CPS-3. To enroll, participants have to answer a brief questionnaire, get their waist measured, and give a blood sample. They also have to agree to the long-term follow-up the study requires.

Enrollment will be taking place in 64 Relay communities across the US during 2007, and will continue at select Relay events through 2011.

The American Cancer Society has a long and successful track record with this type of research. Previous ACS studies (some dating back to the 1950s) have helped identify important cancer risk factors like tobacco use, obesity, air pollution, and others. In fact, these studies were key to discovering that smoking can cause lung cancer and that being obese raises the risk of developing several types of cancer.

"We are once again looking to the dedication, compassion and generosity of Americans to come through and help us provide answers that we know will save lives and improve the outlook for future generations," Calle says.

The CPS-3 will build on the information from the older CPS studies, as well as more recent scientific discoveries.