For instance, mutations in the DICER1 gene, coding for an RNase III endoribonuclease involved in microRNA biogenesis, were identified as a rare event in adult TCs (5, 11–16), whereas they were more frequently reported in pediatric TC patients (8, 17–20) and in carriers of the DICER1 syndrome (21–27), an inherited cancer-predisposing disorder caused by germline DICER1 mutations. This evidence concerns the gene DICER1 and cancer.