CILP2 overexpression correlates with tumor progression and poor prognosis in patients with colorectal cancer in the study of The Cancer Genome Atlas (TCGA) and our cohort analysis

Abstract

Background: Genetic alterations play an important role in the progression of colorectal cancer. Identifying new biomarkers to assess the prognosis of patients with colorectal cancer is critical. Cartilage Intermediate Layer Protein 2 (CILP2) gene, screened from the TCGA database by bioinformatics, may be closely related to the progression of colorectal cancer. CILP2 was barely reported with clinical features of tumors.Materials and methods: Clinical information and RNA-seq data were derived from the TCGA colorectal carcinoma cohort. CILP2 expression at mRNA level was estimated by bioinformatical analysis of TCGA cases. Tissue microarray (TMA) was constructed containing paraffin-embedded 64 pairs of colorectal cancer and matched adjacent normal tissues. The expression at the protein level was detected in 64 pairs of colorectal cancer and matched adjacent normal tissues by immunohistochemical analysis. CILP2 expression level and its clinical value were estimated by bioinformatical analysis with linear and logistic regression. Survival analysis was performed between high and low groups of CILP2 expression by Cox regression analysis, and the P-value was calculated by the log-rank test. Kaplan-Meier curves were tested by the log-rank test.Results: CILP2 was statistically significantly higher expressed in the colorectal cancer tissues when compared with paired adjacent normal tissues in the TCGA cohort (P<0.001) and in the TMA cohort (P=0.001). Also, CILP2 high-expression was strongly correlated with T3/4 stage (P=0.001), N1/2/3 stage (P=0.005), M1 stage (P=0.048), and higher clinical stage (UICC 2010 stage) (P<0.001) in TCGA cohort, and also positively associated with T3/4 stage (P=0.022) and higher clinical stage (UICC 2010 stage) (P=0.03) in TMA cohort. Furthermore, CILP2 overexpression predicted poor prognosis and could be as an independent prognostic factor (P=0.003).Conclusion: We revealed that CILP2 is associated with advanced stages and could play a role as an independent predictor of poor survival in colorectal cancer.