DICER1 and cancer: Based on the structure of DICER1, the catalytic site, where the pre-miRNA is cleaved is mainly formed by the residues S1344 in the RNase IIIa domain, responsible for cleaving the 3p arm, and E1705, D1709 and E1813 in the RNase IIIb domain, responsible for cleaving the 5p arm [133], which are also the residues that are most often mutated in ETMR and other cancers [86, 133].