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

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 17q21.31and 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.