Extended miRNA expression validation in thyroid nodules with DICER1/DGCR8 mutations. (A) Top: expression levels of 3 selected miRNAs using global miRNA profiling via nanoString; middle: relative expression levels of the same 3 selected miRNAs validated experimentally by quantitative RT-PCR; bottom: expression levels of the same 3 selected miRNAs extracted from TCGA data. (B) Disabling mutations in RNase III domains of DICER1 lead to 5p miRNA depletion. Schematic representation of the mechanism by which DICER1 cleaves pre-miRNA in wild-type and mutated conditions; hotspot mutations in the RNase IIIb domain lead to a significant reduction of 5p strand miRNAs in DICER1 mutants compared with wild-type cases. The figure was created with Biorender.com. (C) Remarkable difference in 5p:3p strand ratio between DICER1 mutants and wild-type cases was observed in the Karolinska cohort.