Description
We show that numerous miRNAs are transcriptionally up-regulated in papillary thyroid carcinoma (PTC) tumors compared with unaffected thyroid tissue. Among the predicted target genes of the three most upregulated miRNAs (miRs 221, 222 and 146b), only less than 15% showed significant downexpression in transcript level between tumor and unaffected tissue. The KIT gene which is known to be downregulated by miRNAs 221 and 222 displayed dramatic loss of transcript and protein in those tumors that had abundant mir-221, mir-222, and mir-146b transcript.