Focusing only on cMNRs of increased length (>7 nt) we found overall very low mutation frequencies in NMD factor genes with the notable exception of the A9 repeat in UPF3A. This indicates that mutations in the overall NMD pathway are not positively selected for, possibly emphasizing the role this pathway plays in preventing an immune reaction against the emerging tumor. Here, UPF3A is linked to neoplasm.