Familial Cancer Clinic Helps Families Make the Most Important Decision
When Marc Myers was 5 years old, he was treated for acute lymphoblastic leukemia. His 39-month chemotherapy treatment was successful.
But when Marc started high school in Champaign, Ill., last fall, the 14-year-old teen was much shorter than most of his peers. At 4 ft. 11 in., the freshman in high school had fallen off the growth curve and stopped growing.
Marc's parents brought him to a pediatric endocrinologist, who diagnosed growth hormone deficiency. The endocrinologist suggested the teen might be a candidate for human growth hormone (HGH) treatment. But before moving forward, Marc's family history needed to be considered along with his personal medical history.
Jerry Myers, Marc's father, had been diagnosed and treated for colon cancer in 2001. Testing at the University of Chicago's Cancer Risk Clinic revealed that he had a hereditary colon cancer syndrome and carried the genetic mutation HNPCC. The risk of passing the mutation on to each offspring is 50%.
The dilemma faced by the family and the doctors: HGH can be procarcinogenic (linked with causing cancer). It accelerates cell division, and in the case of colon cancer cells, it has been shown to promote their growth. If Marc carried the same genetic mutation as his father, treating him with HGH could prove detrimental.
"We had a decision to make and there were life-altering consequences on either side of that decision," says Suzanne Lee, Marc's mother. "We needed to know if the medical and social benefits of taking HGH outweighed the possible risk of colon cancer."
The search for more information brought the Myers family to the University of Chicago Medicine Familial Cancer Clinic. The clinic is the pediatric component of the University of Chicago's Cancer Risk Clinic, where Jerry Myers had been tested five years earlier.
Under the direction of hematologist/oncologist Kenan Onel, MD, PhD, the Familial Cancer Clinic's research program focuses on the genetic basis of cancer and on the variations in genetic makeup that contribute to cancer risk. This research is tied directly to patient care.
"Dr. Onel was uniquely able to understand all the different issues in our very complicated situation," says Marc's mother. "He had all the components: expertise in hereditary disease, pediatrics, and cancer. The first time Dr. Onel talked to us, he picked up right away on what we needed. It was a life-changing phone call."
The family worked with the team of doctors, nurses, and genetic counselors to reach the decision to test the teen for the HNPCC mutation.
"We decided that Marc's situation was compelling enough to warrant genetic testing at an early age," says Dr. Onel. "We were able to give the family good news. The blood test revealed that Marc did not inherit the mutation that leads to colon cancer."
In late 2006, Marc started human growth hormone treatment. Marc's mother sees the treatment as a way for her son not only to grow taller, but also to become more confident. And having the knowledge that Marc does not have the mutation has relieved a lot of anxiety for the family. "For families with cancer, there is so much that is out of our control. Worrying about Marc inheriting the gene can be crossed off the list."
Finding Clues to the Genetic Basis of Cancer
By testing Marc Myers for the genetic mutation known to be carried by his father, the Familial Cancer Clinic provided the Myers family with information critical to the teen's current therapy and to his future cancer risk.
Identifying the presence or absence of a genetic mutation and recommending a highly individualized treatment plan form the basis of the important research by Dr. Onel and his team. His studies, funded by the NIH and the American Cancer Society, focus on how genetic variations contribute to cancer risk. The goal is to discover the critical genetic factors that either promote or prevent the development of cancer, eventually charting a road map to identify cancer risk.
In one study, Dr. Onel's laboratory is using an advanced technology called genotyping microarrays to compare genetic differences across their entire genome between children who develop a second cancer and those who do not. With this information, doctors could one day develop treatment plans that fight the first cancer without increasing the risk of a second cancer.
In another study, Dr. Onel is working to map the genetic differences among patients who have acute lymphoblastic leukemia (ALL). While the cure rate for ALL is close to 90%, there are still a significant number of children who die from the disease. By using a new technology that rapidly identifies genetic alterations throughout the entire genome, Dr. Onel hopes to identify genetic "markers" to detect which children might not survive. These patients could then receive more aggressive treatment from the beginning of therapy.
Finding and understanding the genetic differences in children who develop second cancers and in patients with ALL may lead to simple blood tests which will enable physicians to assess each patient's risk of cancer. With a better understanding of a patient's genetic makeup, doctors would then design more advanced individualized prevention strategies.
"We not only treat the patients, we learn from them," says Dr. Onel. "And that knowledge will lead to better therapies in the future."