Among extracellular non‑coding RNAs, serum levels of microRNAs have been extensively investigated in cancers. In contrast, the serum levels of vault RNAs (vtRNAs) in relation to various disease conditions remain poorly understood. The present study evaluated the clinical significance of serum vtRNA1‑1 levels in patients with blood diseases. The stability and sub‑localisation of serum vtRNA1‑1 was assessed and a reverse transcription‑quantitative PCR method using spiked RNA to quantify serum vtRNA1‑1 was developed. Serum vtRNA1‑1 levels were assessed in 102 individuals with blood diseases. Serum vtRNA1‑1 was demonstrated to be stable for three weeks at 4˚C and was not confined to the exosome fractions. Spiking RNA was used to correct for the inconsistency in RNA extraction. The serum vtRNA1‑1 levels ranged between 7.28 and 8.76 log10 cps/ml (median 8.05) in control individuals (n=46). Serum vtRNA1‑1 levels correlated with leukocyte counts and increased to a maximum of 10.01 log10 cps/ml in patients with bulky leukaemia and lymphoma and decreased to 6.52 log10 cps/ml during intensive chemotherapy. The serum vtRNA1‑1 levels varied significantly in patients with haematological malignancies. Serum vtRNA1‑1 may originate from haematological cells and are a potential biomarker of normal and malignant haematological activities.
Keywords: biomarker; exosome; extracellular vesicle; haematological malignancy; vault RNA.