To investigate the expression, clinical significance, and biological function of the long non-coding RNA (lncRNA) ADAMTS9-AS2 in colorectal cancer (CRC).
 Methods: Gene microarray analysis was performed to explore the expression of ADAMTS9-AS2 in CRC. Real-time PCR was used to verify its expression in 20-paired CRC tissues and adjacent non-tumor tissues. We further explored the relationship between ADAMTS9-AS2 expression and clinicopathological features, and its prognostic role in relapse-free survival (RFS) among early stage CRC patients using Kaplan-Meier and Cox regression analyses. In vitro assays, cell counting kit-8 assay, colony formation assay, and Transwell assay were used to evaluate the biological function of ADAMTS9-AS2 in CRC.
 Results: ADAMTS9-AS2 was down-regulated in CRC patients according to the gene microarray analysis, which was confirmed in CRC tissues and cells. High expression of ADAMTS9-AS2 was associated with a higher 5-year RFS rate (83.8% vs 73.5%, P=0.041) and it was an independent prognostic factor for RFS [hazard ratio (HR)=0.528; 95% CI 0.299 to 0.932; P=0.028] at the early stage of CRC. ADAMTS9-AS2 overexpression in CRC cells inhibited cell proliferation, migration, and invasion, while suppression of ADAMTS9-AS2 showed opposite effects.
 Conclusion: ADAMTS9-AS2 is a valuable prognostic factor for CRC and may function as a tumor suppressor in CRC via inhibiting cell proliferation and metastasis.
ADAMTS9 Protein ; genetics ; Cell Movement ; Cell Proliferation ; Colorectal Neoplasms ; genetics ; Gene Expression Regulation, Neoplastic ; Humans ; Neoplasm Recurrence, Local ; RNA, Long Noncoding