Prognostic significance of lymphovascular invasion in colorectal cancer and its association with genomic alterations

BACKGROUND: Lymphovascular invasion (LVI) is suggested to be an early and important step in tumor progression toward metastasis, but its prognostic value and genetic mechanisms in colorectal cancer (CRC) have not been well investigated. AIM: To investigate the prognostic value of LVI in CRC and identify the associated genomic alterations. METHODS: We performed a retrospective analysis of 1219 CRC patients and evaluated the prognostic value of LVI for overall survival by the Kaplan-Meier method and multivariate Cox regression analysis. We also performed an array-based comparative genomic hybridization analysis of 47 fresh CRC samples to examine the genomic alterations associated with LVI. A decision tree model was applied to identify special DNA copy number alterations (DCNAs) for differentiating between CRCs with and without LVI. Functional enrichment and protein-protein interaction network analyses were conducted to explore the potential molecular mechanisms of LVI. RESULTS: LVI was detected in 150 (12.3%) of 1219 CRCs, and the presence was positively associated with higher histological grade and advanced tumor stage (both P < 0.001). Compared with the non-LVI group, the LVI group showed a 1.77-fold (95% confidence interval: 1.40-2.25, P < 0.001) increased risk of death and a significantly lower 5-year overall survival rate (P < 0.001). Based on the comparative genomic hybridization data, 184 DCNAs (105 gains and 79 losses) were identified to be significantly related to LVI (P < 0.05), and the majority were located at 22q, 17q, 10q, and 6q. We further constructed a decision tree classifier including seven special DCNAs, which could distinguish CRCs with LVI from those without it at an accuracy of 95.7%. Functional enrichment and protein-protein interaction network analyses revealed that the genomic alterations related to LVI were correlated with inflammation, epithelial-mesenchymal transition, angiogenesis, and matrix remodeling. CONCLUSION: LVI is an independent predictor for survival in CRC, and its development may correlate with inflammation, epithelial-mesenchymal transition, angiogenesis, and matrix remodeling.