CT chest scanning has been recommended to screen for pleuropulmonary blastoma (PPB) in babies and young children known to harbor germline DICER1 mutations. However, only a minority of these patients will develop PPB, and the use of CT scans is associated with risks such as secondary malignancy. Recently, we identified a panel of microRNAs that were highly abundant in the serum of a patient with a germline DICER1-mutated PPB, but present at normal levels in healthy relatives carrying the same germline mutation. Consequently, we advocate the addition of serum microRNA profiling to this programme of radiological surveillance, in order to establish its clinical utility as a PPB biomarker. If validated, this blood-based screening-tool may reduce our reliance on CT imaging.