Rhabdomyosarcoma is an aggressive solid
tumor that may disseminate hematogenously giving
metastasis which represents the most important prognostic factor. Chances of an effective cure in childhood
cancer rely on the capacity to make an early and accurate diagnosis, detect metastatic disease or relapse, and predict the response to treatment.Liquid biopsy is a very promising blood test for
cancer detection and noninvasive disease monitoring. This method has a great advantage to use blood and plasma, a more accessible biological material, quick and easy to obtain with minimal
pain and risk for patients. In particular, circulating free
DNA (
cfDNA) represents a
tumor biomarker detected in plasma that gives information on biology and genetic background of
tumor.Moreover,
cfDNA mutation detection could be a reliable method to monitor the efficacy of treatment and to discover novel targets for a personalized treatment in pediatric solid
tumor. Here, we describe an optimized protocol to
cfDNA isolation from small amount of plasma, as well as a method to assess the quantity and quality of
cfDNA. Finally, we propose ddPCR as a reliable method to detect mutations at low frequency in
cfDNA obtained from pediatric
rhabdomyosarcoma samples.