Cancer CellsEat healthy. Don’t smoke. Avoid alcohol. Exercise. These are the long-held pillars of avoiding cancer. However, a new study published in the journal Science says you might want to add one more to your daily regime:

Cross your fingers.

The study, led by researchers at the Johns Hopkins School of Medicine, found that only one-third of cancers were due to heredity or environmental factors. The study suggests that two-thirds of cancers are due to the bad luck of random mutation in the otherwise natural cellular division of stem cells.

This study confirms what clinicians have long understood about cancer, said Judy Smith, MD, chief of oncology for Spectrum Health Medical Group.

“It is well known that cancer often develop from a series of random mutations and occurs more frequently in organs with more dividing cells,” she said.

Spectrum Health’s Clinical Genetics Director, Helga Toriello, PhD, agreed.

“It’s like people who drive a lot more – they’re a lot more likely to have an accident,” she said. “And though the study seemed to imply it’s random, in fact, environmental factors lead to increased chance of mutation. For example, the minute you walk out into the sun, the ultraviolet radiation causes mutations to occur, but your body has a repair mechanism in place. At some point, it won’t keep up.”

The researchers studied 30 types of stem cells, the specific cells in each organ or tissue that are tasked with replacing other worn-out cells. The more often stem cells are required to divide, the more likely for mutations to occur and lead to cancer, the study showed.

“Stem cells are the cells in charge of the creation of new cells,” Dr. Smith explained. “Your body is constantly developing new cells. Take for example, your skin. When you cut your skin, it grows back together. You get an ulcer in your mouth, it heals. Each part of your body has a different rate of turnover of those cells. This study took our basic knowledge of cancer one step further and measured the stem cell content of organs and used an innovative mathematical model to assign cancer risk. This study confirmed that those organs with higher cell division rates also have higher stem cell content, and a higher risk for cancer.”

Some 13.2 million people develop cancer each year worldwide, according to the American Cancer Society, while another 8 million people die from cancer-related illness each year. The ACS projects there will be an estimated 1,658,370 new cancer cases diagnosed and 589,430 cancer deaths in the U.S. this year alone.

Dr. Smith said this study opens the door to new thinking about treatment – and prevention.

“I think it just gives us additional information about the importance of genomics and personalized medicine,” she said. “As we move forward, particularly at the Regional Cancer Center, this can lead us into more personalized therapy.

“It’s important to focus not only on a healthy lifestyle, but also on screening and early detection. While some of this might be hit and miss, don’t underestimate the benefits of early detection to increase the chances for a cure.”

Dr. Toriello agreed, and stressed not leaving it all to chance.

“Luck is a part of it, but it’s only part of the picture, not the whole picture,” she said. “I would still say do everything you can to reduce the risk of developing cancer. Avoid things like cigarette smoking, avoid excessive sun exposure … avoid things that are known to increase risk of cancer.

“And, if you have a family history of cancer, that could indicate that you might fall into the group of people who do have an increased genetic risk. Make sure to discuss your family history with your physician.”