<p>Serum Exosomal Long Noncoding RNA pcsk2-2:1 As A Potential Novel Diagnostic Biomarker For Gastric Cancer</p>

Abstract

Exosome-shuttled bioactive long non-coding RNA, as novel non-invasive biomarkers for cancer diagnosis, has received increasing attention. Here, we aimed to investigate the expression of serum exosomal long non-coding RNA pcsk2-2:1 (Exo-Lnc RNApcsk2-2:1) in patients of gastric cancer and evaluate its diagnostic value as a marker. Patients and methods: Exosomes were isolated from serum sample of gastric cancer using HiPure Exosomekits and identified via transmission electron microscopy, Western blotting, and nanoparticle tracking analysis. The total exosomal RNA was extracted and reverse transcribed to cDNA. The expression of Exo-Lnc RNA PCSK2-2:1 was detected in serum exosomes of 29 healthy people and 63 gastric cancer patients by real-time quantitative reverse transcription PCR (qRT-PCR), and the relationship between the expression level of Exo-Lnc RNA PCSK2-2:1 and clinicopathological parameters of patients was analyzed. Finally, a receiver operating characteristic curve was used to evaluate the clinical value of Exo-Lnc RNA PCSK2-2:1 as an auxiliary diagnostic marker for gastric cancer. Results: Transmission electron microscopy, nanoparticle size analysis, and Western blotting showed successful separation of serum exosomes. qRT-PCR results revealed that compared with the healthy control, Lnc RNA PCSK2-2:1 expression level in serum exosomes of gastric cancer patients was significantly downregulated (p=0.006). Moreover, the expression level of Exo-Lnc RNA PCSK2-2:1 was correlated with tumor size (p=0.0441), tumor stage (p=0.0061), and venous invasion (p=0.0367). The area under the curve of Exo-Lnc RNA PCSK2-2:1 was 0.896. At the optimal cutoff value, the diagnostic sensitivity and specificity were 84% and 86.5%, respectively. Conclusion: Our data indicate that Exo-Lnc RNA PCSK2-2:1 may perform a vital role in the progression of gastric cancer and can be used as a potential marker for the diagnosis of gastric cancer.

<p>Evaluation of Serum Exosomal lncRNAs as Diagnostic and Prognostic Biomarkers for Esophageal Squamous Cell Carcinoma</p>

“…Recent observations have demonstrated that numerous lncRNAs are present in exosomes of cancers and show great potential as non-invasive tumor markers. 31…”

The Significance of Exosomal RNAs in the Development, Diagnosis, and Treatment of Gastric Cancer

“…Recently, studies validated that exosomal lncRNAs can also serve as tumor biomarkers for GC. Chenchen suggested that the exosomal expression of LncRNA PCSK2-2:1 of GC patients was markedly downregulated compared to the control group, and was correlated with tumor size, stage, and venous invasion [ 102 ]. This study and researches alike validated the possibility to use lncRNAs to predict metastasis and prognosis of GC.…”

Identification of serum exosomal lncRNA MIAT as a novel diagnostic and prognostic biomarker for gastric cancer

“…12 For instance, the expression of serum exosomal lncRNA PCSK2-2:1 was significantly reduced in patients with GC, and downregulation of serum exosomal lncRNA PCSK2-2:1 was associated with adverse clinical parameters of GC. 13 Similarly, serum exosomal lnc-GNAQ-6:1 level was lower in GC patients and exhibited good performance for discriminating GC patients from healthy volunteers. 14 Myocardial infarction associated transcript (MIAT) was first identified as a lncRNA in 2006 and mapped to human chromosome 12q12.1.…”

“…LncRNAs are found in circulating exosomes and might be used as candidate biomarkers for the detection and prognosis prediction of cancers 12 . For instance, the expression of serum exosomal lncRNA PCSK2‐2:1 was significantly reduced in patients with GC, and downregulation of serum exosomal lncRNA PCSK2‐2:1 was associated with adverse clinical parameters of GC 13 . Similarly, serum exosomal lnc‐GNAQ‐6:1 level was lower in GC patients and exhibited good performance for discriminating GC patients from healthy volunteers 14 …”