Mutation Scanning of D1705 and D1709 in the RNAse IIIb Domain of MicroRNA Processing Enzyme Dicer in Cutaneous Melanoma.

Since the discovery of microRNAs (miRNAs) there have been performed several studies showing perturbations in the expression of miRNAs and the miRNA expression machinery in cutaneous melanoma. Dicer, a pivotal cytosolic enzyme of miRNA maturation has shown to be affected by both somatic and germline mutations in a variety of cancers. Recent studies have shown that recurrent somatic mutations of Dicer frequently affect the metal-ion-binding sites D1709 and D1705 of its RNase IIIb domain, therefore called hot spot mutations. The present study investigates metal-ion-binding sites D1709 and D1705 of the Dicer RNase IIIb domain in cutaneous melanomas and melanoma metastasis by Sanger sequencing. All investigated samples showed wildtype sequence and no single mutation was detected. The miRNA processing enzyme Dicer of melanoma and melanoma metastasis does not appear to be affected by mutation in the metal-ion-binding sites D1709 and D1705 of its RNase IIIb domain.