Evaluation of the Association Between CRNDE Plasma Expression Level, KRAS, NRAS, and BRAF Variants in Patients with advanced CRC

Colorectal cancer is one of the most common types of cancer. CRNDE is a novel-defined lncRNA. We evaluated the possibility of using CRDNE circulating lncRNA as a noninvasive biomarker. Also, we examined the effect of circulating CRNDE lncRNA on the pathogenesis of CRC and its association with the KRAS, NRAS, and BRAF somatic variants commonly observed in CRC. In this study, we enrolled plasma and FFPE tissue samples of 50 advanced CRC patients and plasma samples of 31 individuals in the control group of similar ages. Then, we performed plasma extraction, total RNA isolation, cDNA synthesis, and circulating lncRNA expression analysis, respectively. Also, we carried out KRAS, NRAS, and BRAF somatic variant analysis from FFPE tissues. Our results showed that the expression level of CRNDE (p= 0.002) were significantly upregulated in the CRC when it was compared to with the control group. The calculated area under the curve of the receiver operating characteristic was 0.70. We found a statistically significant difference between the KRAS somatic variants and the circulating CRNDE lncRNA (p= 0.031). This study demonstrated that CRNDE circulating lncRNAs may be used as a potential non-invasive biomarker in CRC. In our study, it was determined that there is a significant relationship between the frequently observed KRAS somatic variants and CRNDE in advanced-stage CRC cases. To the best of our knowledge, this is the first study to show the association of CRNDE circulating lncRNA with advanced CRC. Moreover, it is the first study to show a relationship between the KRAS somatic variants between circulating CRNDE lncRNA in advanced CRC.