Upregulation of Dicer is more frequent in monoclonal gammopathies of undetermined significance than in multiple myeloma patients and is associated with longer survival in symptomatic myeloma patients

Dicer and Drosha are key enzymes in the miRNA-processing pathway which is altered in many human cancers.We analyzed Dicer and Drosha expression levels by quantitative PCR in 151 patients with monoclonal gammopathies: 102 symptomatic myeloma patients, 23 smoldering myelomas and 26 monoclonal gammopathy of undetermined significance. We found that Dicer expression values were significantly higher in monoclonal gammopathy of undetermined significance than in smoldering myelomas and symptomatic myeloma (mean ± SD, 0.84±0.36 vs. 0.60±0.23 and 0.62±0.51; P