In many cases, cancer is a lifestyle disease. You are far more likely to get lung cancer if you smoke and the older you get, the more likely you are to get cancer of all kinds. Age is the biggest risk factor and we get more cancer than our ancestors because they died from a lot of other things before cancer could develop.

But what about cancer in kids? A pediatric study of cancer predisposition genes in New England Journal of Medicine discusses new scientific discoveries regarding how cancer develops in children. That study, by a team from St. Jude's Research Hospital led by Dr. James R. Downing, found that 8.5 percent of children and adolescents with cancer in their sample of 1120 patients had mutations known to raise their risk of cancer. Less than half of children who inherited those cancer predisposition genes had a family history of cancer. 

In the majority of cases in the study, a child's inherited cancer-predisposition mutation did not seem to lead to cancer in the parents or in other family members. As gene sequencing tools and genetic science itself continue to advance, clinicians will need to better counsel family members on the implications of previously unrecognized cancer predisposition genes in their family.

In an accompanying editorial, John M. Maris, M.D., a pediatric oncologist at The Children's Hospital of Philadelphia (CHOP), credits the new study as "the most comprehensive blueprint to date of genetic childhood-cancer predisposition," adding that the full complexity of how children develop cancer remains to be investigated. And because some cancer-related mutations may also increase the risk that a childhood-cancer survivor may later develop a second cancer, clinicians and cancer researchers will need to develop the most effective strategies for counseling patients "through the continuum of infancy to old age."  

"Like all good research, this new study opens up more questions and areas for more investigation," said Maris. "At the very least, this work should remind clinicians that we need to look beyond family history in treating and counseling pediatric cancer patients and their families."