IN THE Netherlands, there is only one hospital that treats all children with cancer. It is the Princess Máxima Center for Pediatric Oncology, the largest child cancer center in Europe, whose researchers have just published a study on a genetic test that can improve diagnosis and choice of treatment. The test is based on RNA sequencing which, in their analysis, revealed 40% more molecular alterations in tumors than traditional investigations. Application of this test to young patients who arrived in the past six months resulted in a change in diagnosis or improved therapy in seven cases, as described in the JCO Precision Oncology.
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Identify the fusion genes
Between late 2018 and mid-2019, tumor tissue samples from 244 children were analyzed. The research team focused on fusion genes, a type of defect in which parts of two different genes join together to form a new defective gene. Through the sequencing method, the team identified a total of 78 fusion genes, which is 23 more (corresponding to 40%) than those found with standard techniques. Who have identified 55 mutations, but often giving information only on one of the two genes involved in the fusion, when the information relating to both genes can be very important for the therapeutic choice. “RNA sequencing had been used before, but only in very sick children for whom traditional treatment had ceased to benefit,” explains Bastiaan Tops, Head of the Diagnostic Laboratory at the Princess Máxima Center for Pediatric Oncology, among the study coordinators: “We have now implemented traditional diagnostic techniques with RNA sequencing techniques, so we are able to examine the entire genetic landscape of the tumor already at the time of diagnosis and to choose the most effective treatment. In this way, we are able to intervene with a timeliness that was unthinkable until recently “.
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More accurate diagnosis for seven children
In fact, one-third of the 23 gene fusions detected with RNA sequencing led to a more accurate diagnosis or more appropriate treatment. In the case of one girl, for example, it was possible to arrive at the diagnosis of childhood fibrosarcoma (a soft tissue tumor) with a gene fusion of NTRK for which there are target drugs. In a child with a brain tumor, sequencing revealed that it was not glioblastoma, as initially diagnosed, but hemispheric glioma, a less aggressive type of tumor, and was given a more appropriate drug than stabilized his condition for a further year.
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The researchers hope to be able to use RNA sequencing techniques to analyze other cancers as well, particularly the different forms of leukemia. “With all the anomalies that this method has allowed us to identify, we have been able to make new and more precise diagnoses of tumors on children already under treatment”, concludes Patrick Kemmeren, group leader and head of the Big Data Core at the Princess Máxima Center and one of the coordinators of the research: “The study has in fact shown that in pediatric cancers a single genetic test of tumor RNA is almost one and a half times more sensitive than standard techniques. I therefore expect that in the near future it will completely replace traditional methods “.
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Image credits: James Gathany via Unsplash