BACKGROUND: Late diagnosis and metastasis are leading causes of the high mortality of colorectal cancer (CRC). Long noncoding RNAs (lncRNAs) have been reported to play a critical role in the development and progression of CRC. This study aimed to explore the clinical significance of 2 novel lncRNAs – RP11-296E3.2 and LEF1-AS1 – including their expression pattern, as well as diagnostic and prognostic values, for metastatic CRC patients.

MATERIAL AND METHODS: lncRNAs expression was examined in tissues (91 cases) and plasma (60 cases) from CRC patients by real-time quantitative PCR (qRT-PCR), and the correlations between its expression and clinicopathological features and diagnosis values in metastasis were analyzed. TCGA datasets were further used to analyze their utility in prediction of overall survival (OS) and disease-free survival (DFS). ATP-based tumor chemosensitivity assay (ATP-TCA) was used to evaluated tumor chemoresistance.

RESULTS: Compared with adjacent normal tissues, RP11-296E3.2 was significantly downregulated while LEF1-AS1 was significantly upregulated in cancer tissues (p=0.0143, p=0.0322, respectively). High levels of RP11-296E3.2 and LEF1-AS1 in tissues and plasma were correlated with tumor metastasis (p=0.0488, p=0.0252 in tissues, p=0.0331, p=0.1862 in plasma, respectively). Further analysis showed that RP11-296E3.2 sensitivity and specificity in diagnosis of CRC metastasis is better than CEA in plasma (0.690 and 0.621, and 0.621 and 0.500, respectively), and the OS of metastatic CRC patients with higher LEF1-AS1 expression levels in tissues was short (log-rank p<0.05).

CONCLUSIONS: Our findings suggest that RP11-296E3.2 and LEF1-AS1 could separately serve as potential novel diagnosis and prognostic markers for CRC metastasis.

Keywords: Biological Markers, Colorectal Neoplasms, Biomarkers, Tumor, Drug Resistance, Multiple, ROC Curve, Reproducibility of Results