California Initiative to Advance Precision Medicine California Kids Cancer Comparison

Whereas adult cancers are often linked to genetic mutations that are acquired during an individual’s lifetime, such as through environmental exposures, pediatric cancers present with fewer mutations and are therefore more difficult to diagnose. Support for and advancement of adult cancer therapies continue to progress compared to pediatric cancers, due in large part to ample federal funding, the underlying biology of adult cancers, more established data sharing platforms, and the drug development pipeline. Childhood cancers are significantly less common, which ultimately limits clinical trials from recruiting sufficient numbers of patients and makes drug development a much slower process than for adult cancers. Pediatric cancers also tend to be more complex, which prevents a single therapy from benefitting large groups of patients. Of federal funding allocated to the National Cancer Institute, approximately 4% is annually designated for pediatric cancers.

Until 2017, cancer drugs were developed to target specific mutations based on where a tumor was located within the body (e.g., lung cancer). These targeted drugs work by interfering with the ability of cancer cells to grow or survive. They are effective as long as the patient's tumor has the most common mutation the drug is designed to target. Occasionally, a mutation known to occur in one tumor type is detected in a tumor in a different location of the body. For instance, a mutation typically found in lung cancer may be found in a brain tumor. Since the drug is targeted to prevent or reverse the negative effects of that mutation, it may help treat the brain cancer, even though it was originally developed for lung cancer. Advanced DNA sequencing allows clinicians to uncover a patient's specific cellular mutations and can help direct the treatment strategy.

Consider the analogy of DNA as the full set of blueprints of a building site and RNA as the daily orders for a construction crew. Scientists can uncover which genes are active by identifying the collection of RNA molecules present in a cell. This set of RNA molecules is known as a cell's transcriptome, and the scientific study of it is called transcriptomics. By comparing RNA molecules that are detected in a patient's tumor to those found in thousands of other tumors (comparative RNA analysis), scientists can ascertain how the molecular pattern of a patient's tumor resembles or differs from other tumors. This information can help guide the best treatment strategy based on the underlying mechanisms of tumor growth.