SACRAMENTO, Calif. -- The American Cancer Society is recruiting 500,000 people for a huge study to learn what causes and prevents cancer.

"I lost my dad 14 months ago so it takes on a whole new meaning," said Teresa Rodriguez.

Rodriguez has no idea why her father Ruben got a rare form of cancer. But she's signing up for a study that may provide some future answers.

It's called the Cancer Prevention Study-3. The American Cancer Society is looking for 500,000 volunteers who are willing to have their waists measured and their blood drawn once at the beginning. Then they will fill out questionnaires about their health and lifestyles over the next 20 years. Participants need to be between 30 and 65 years old with no history of cancer.

"Within that 20 years certainly some people will get cancer, many won't," said epidemiologist Monica Brown. "What we'll learn is what makes those two groups different. That is vastly important to all of us."

This is the third study of its type. The first was launched in the 1950s . The second started in the 1980s . Now, researchers are recruiting a younger pool of volunteers.

Past American Cancer Society studies have led to groundbreaking discoveries about how fruits and vegetables can help prevent cancer. Results have also shown that hormone replacement therapy may be unsafe for some women. This latest study will undoubtedly lead to new guidelines making us more aware of what can cause or prevent cancer.

Deryl Wallace is a program manager for the American Cancer Society. She also has another reason to sign people up for this study.

"I'm a two-time cancer survivor. So it means a lot to me to know that people are stepping and saying I want to do something about it, I want to give back," Wallace said.

That's why Rodriguez is volunteering in the memory of her father.

"In a tribute to him and to everyone we have lost in our families," Rodriguez said.

This is a $35 million national study. Because the American Cancer Society does research with volunteers, the cost is lower than other institutions have to spend on research of this magnitude. The Sacramento chapter of the American Cancer Society is signing people up at the Relay for Life events in Elk Grove on Saturday, May 17, and also at the event in Modesto on June 21.

For more information, call toll-free 1-888-604-5888.