CILP2 overexpression predicts poor prognosis in colorectal cancer

Abstract

Background Cartilage Intermediate Layer Protein 2 (CILP2), a glycoprotein with mutations associated with abnormal blood lipid concentrations in normal and cardiovascular diseases patients, was barely reported with clinical features of tumors. We evaluated the role of CILP2 among all stages and histology in colorectal cancer (CRC) in the Cancer Genome Altas (TCGA), and furtherly verified using immunohistochemistry assay within human CRC tissues. Materials and methods Clinical information and RNA-seq data were derived from 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 CRC and matched adjacent normal tissues. The expression at protein level was detected in 64 pairs of CRC 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 P value was calculated by log-rank test. Kaplan-Meier curves were tested by log-rank test. Results CILP2 was significantly higher expressed in the colorectal cancer tissues when compared with paired adjacent normal tissues in TCGA cohort (P < 0.001) and in TMA cohort (P = 0.001). In addition, 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.