DICER1 and DICER1-related tumor predisposition: In contrast with the initially proposed theory of haploinsufficiency of this tumor suppressor gene as the cause underlying DICER1 syndrome [5], our results support the hypothesis that patients harboring a loss-of-function germ-line DICER1 mutation acquire a second somatic hit during tumorigenesis, resulting in a modified enzyme activity, at the RNAseIIIb level [6].