RNU2-1 gene copy number variations do not affect serum levels of miR-1246 as a biomarker for lung adenocarcinoma.

Abstract

Circulating microRNA (miR)-1246, a fragment of U2 small nuclear RNA, represents a promising biomarker for certain cancers, including lung adenocarcinoma. The gene that encodes miR-1246, RNU2-1, is located on human chromosome 17q21.31 and is organized as a tandem array that exhibits copy number variations (CNVs). The range of copy numbers has been reported to be quite wide, ranging from 5 to 82 per haploid genome. The present study analyzed the correlation between RNU2-1 copy numbers and serum miR-1246 levels in healthy controls and patients with stage IV lung adenocarcinoma. Serum miR-1246 levels were quantified using reverse transcription-quantitative polymerase chain reaction (PCR), and RNU2-1 copy numbers per diploid genome were measured via digital PCR using blood-derived DNA. The median copy numbers were 50 and 49 in the control and lung adenocarcinoma groups, respectively, with no significant difference observed between the groups. In addition, no correlation between RNU2-1 copy number and serum miR-1246 level was identified in either group. These results suggest that CNVs of RNU2-1 do not affect serum levels of the lung adenocarcinoma biomarker miR-1246.