A prospective evaluation of liquid biopsy for detecting MYCN amplification in neuroblastoma patients

Background: Our previous study reported a method for determining MYCN gene amplification (MNA) status using cell-free DNA in serum. We prospectively analyzed the serum MNA status using sera obtained before the initial diagnosis from patients with neuroblastoma and evaluated the utility of this method. Methods: Eighty patients were enrolled in the study. The serum MYCN/NAGK ratio was assessed for all cases. Results: Fifteen cases showed serum MNA, while 65 did not. Of the 80 total patients, tumor samples for a genetic analysis were not obtained from 27 due to the patients' condition or other reasons. For the 43 of 80 cases that had both serum and tumor samples analyzed, the serum-based MNA status matched to tumor-based MNA status (P < 0.001). The sensitivity and the specificity were 100%, respectively. Seven of 15 cases who diagnosed as MNA by serum-based MNA status were <18 months of age, and tumor samples were not obtained from 4 of these cases. Based on the serum MNA status, these cases were able to start treatment immediately. The 4-year event-free survival rates of cases with and without MNA in sera were 37.5% and 84.8%, respectively (P < 0.001). Conclusion: The serum-based MNA status was useful for precisely predicting the MNA status in tumor and it has clinical benefits for predicting risk stratification in patients for whom obtaining tumor samples is difficult.