At the annual meeting of the American Association for Cancer Research in Chicago this week, the AACR-ASCO Presidential Symposium focused on research into pediatric cancers. St. Jude Children's Research Hospital's James Downing was on hand to talk about how researchers have been able to unravel these diseases using sequencing. There are marked differences in the kinds of cancers that occur between adults and children, Downing said, and genomics has helped researchers understand those differences, and the different treatments that go along with them. Acute lymphoblastic leukemia is a good example — the survival rate for childhood ALL is now over 90 percent, Downing said, and this is partly due to effective uses of combination therapies, the stratification of patients into different genetic subgroups, the application of molecular diagnostics, and adjusting therapy based on the results. Over the last five years using genome-wide approaches, researchers have made a number of discoveries that have provided new diagnostic and prognostic markers for ALL, he added.
St. Jude's Ching-Hon Pui added that a patient's response to treatment is the most important prognostic factor, and that genomic techniques are now being used to determine treatment response more sensitively and specifically than the traditional morphological approaches. Individualizing dosages reduces toxicity without compromising efficacy, he said, and genomics can also help limit the use of treatments that are associated with late complications and secondary tumors.
Smita Bhatia, from the City of Hope NCI-designated Comprehensive Cancer Center, said survivors of childhood cancers also have a lot of survival complications like secondary tumors, cardiac complications and lung dysfunction because of radiation and chemotherapy. The focus now is using molecular techniques to understand etiology and pathogenesis of adverse effects and how to prevent them, she said. City of Hope has established mechanisms to identify key adverse events and bank DNA and RNA from the patients who suffer them, as well as matched controls, in an attempt to look for genetic susceptibility associated with these events, she added.