All Children with Cancer and Adult Survivors of Childhood Cancer
Should Consider Genetic Testing
Hereditary Connection More Common Than Thought, Suggests Study
CHICAGO – Nov. 19, 2020 – All children with cancer and adult survivors of childhood cancer may benefit from a genetics evaluation, suggests a study that found more than one in five may have a hereditary mutation, which is significantly higher than previously believed. The research is being presented at the National Society of Genetic Counselors (NSGC) 39th Virtual Annual Conference.
Previous studies have suggested about 10% of children with aggressive types of cancer and adult survivors of childhood cancer have a genetic predisposition. The new study assessed a large number of children with more diverse types of cancer and more expansive testing and found 22% tested positive for genetic conditions.
“Children tend to be referred for genetic testing using only specific criteria, meaning we are likely missing many who would benefit from a genetics evaluation, beginning with seeing a genetic counselor,” said Katie Church, MS, CGC, lead author of the study and a genetic counselor at the University of Nebraska Medical Center, Omaha. “Testing a wider variety of genes may uncover mutations that wouldn’t have been identified otherwise. If a mutation is identified, families of children with cancer and their providers can discuss methods to catch cancer sooner, such as additional screening with imaging and blood work or consultation with other specialists.”
The study was conducted at the University of Alabama at Birmingham together with St. Jude Children’s Research Hospital, in Memphis. Researchers assessed genetic test results for 1,070 children with cancer or family histories of cancer and researchers found 233 children (22%) had a genetic mutation. The most commonly identified genes with mutations included NF1 and TP53, which are associated with tumors along the nerves (typically benign but sometimes cancerous) and tumors of the muscle or bone, brain tumors and leukemia.
Further, nearly half (47%) who had large panel testing tested positive for a mutation that wasn’t known be associated with their cancer, although in many cases the significance of that is unknown. Additionally, some family members of children who had a positive result also had genetic testing. For most cancer mutations, first-degree relatives of a child with cancer have a 50% chance of inheriting the mutation. Of the 609 family members tested (including mother, father or sibling), 185 (30%) tested positive for the same mutation.
“We still have a lot to learn about genetics and childhood cancer,” said Church. “There are pros and cons to testing – such as a greater likelihood of receiving uncertain results – which is why family members of children with cancer should meet with an expert such as a genetic counselor to learn more about the benefits and limitations.”