In recent years, researchers have used sophisticated genetic technology to learn a lot more about the genetic changes that lead to cancer. With this knowledge, they have developed new treatments for a variety of cancers based on the unique set of changes in person’s tumour. For example, people with a form of lung cancer caused by a change in a gene called EGFR can be treated with a targeted drug that is not effective in other types of lung cancer.
But we haven’t seen this same type of advance in children’s cancers. There has been progress in treatments, and childhood cancer survival is now 83%, but for the more than 900 children diagnosed with cancer every year in Canada, there is a still a lot of work that needs to be done. Treatments based on genetic changes could be one strategy to improve survival, but they haven’t taken off the same way they have in adult cancers.
One reason for this is that researchers haven’t had the same wealth of information on the genetic changes associated with children’s cancers as they do with adult cancers. But a team of researchers in Memphis analyzed the genetic material of children’s cancers, and the results, published in the journal Nature, surprised them. There were more differences between children’s and adult’s cancers than had previously been thought.
Children’s and adult cancers have key differences
The team analyzed the genetic material of cancer cells from nearly 1,700 children with different types of cancer, including leukemia, neuroblastoma, Wilms tumour (a childhood kidney cancer) and the bone cancer osteosarcoma. By looking at different types of cancer, the researchers could identify the most important genetic changes driving cancer growth.
They used three different types of genetic analysis on the cancer cells, each of which provided different types of information, giving the researchers a complete genetic picture. This information was compared to the same type of information for a variety of adult cancers.
Through the different analyses, the researchers identified unique sets of genetic changes that drive cancer growth in a few different types of cancers, and they also uncovered the types of genetic changes most commonly found in children’s cancers.
But the key finding of the study is that less than half (45%) of the genetic changes drive cancer growth in both adult and children’s cancers, suggesting that these cancers may not be as similar as researchers have believed.
Some treatments designed for adults may not work for children
Researchers commonly believed that cancers affecting both adults and children, such as leukemia or lymphoma, would have similar genetic changes driving cancer growth. But this research suggests that there are more differences than similarities – children are not simply small adults – and treatments that work for adults, specifically those based on genetic changes, may not work in kids.
To use treatments targeted towards cancer’s genetic changes, researchers will need to develop treatments based on those changes found in children’s cancers, and they first need to know what those changes are. This study is one of the first to provide such a complete analysis of the genetic material of children’s cancers, which is critical to helping guide current treatments and developing new ones.
Eileen Hoftyzer, BSc