Abstract:  Objective To investigate the expression of LINC01215 in colorectal cancer (CRC) tissues and its clinical significance. Methods The expression of LINC01215 in CRC tissues and adjacent normal tissues, and its relationship with prognosis were analyzed by TCGA database. The expression levels of LINC01215 in cancer tissue and adjacent normal tissue samples of 137 CRC patients diagnosed and treated in the Second Affiliated Hospital of Guangzhou Medical University from March 2009 to January 2012 were detected by RT-qPCR and the relationship between these expressions and clinicopathological characteristics was analyzed. The LINC01215 target genes were obtained from the MEM website and GO annotation and KEGG analysis were performed. According to the result of functional analysis, single-sample gene set enrichment analysis (ssGSEA) and drug sensitivity analysis were performed on LINC01215. Results TCGA database analysis showed that the expression of LINC01215 in CRC tissues was lower than that of adjacent normal tissues (P<0.001). Clinical specimens verification revealed that the expression of LINC01215 in CRC tissues was lower than that of adjacent normal tissues (P=0.001), and correlated with the degree of tissue differentiation (P=0.037). TCGA database analysis showed that the median overall survival of the high LINC01215 expression group was significantly higher than that of the low LINC01215 expression group ［96 months (95%CI: 80-113 months) vs 82 months (95%CI: 70-95 months), P=0.002］. Low LINC01215 expression was a risk factor for poor prognosis of CRC (HR=1.69, 95%CI: 1.13-2.51, P=0.010). GO and KEGG analysis showed that the target genes related to LINC01215 was mainly involved in protein binding, T cell receptor signaling pathway and other pathways. ssGSEA analysis found that LINC01215 was associated with 28 immune cells (all P<0.05). Drug sensitivity analysis showed that LINC01215 was related to the drug sensitivity of Chelerythrine, Sapacitabine, Hydroxyurea and Fenretinide (all P<0.05). Conclusions LINC01215 is lowly expressed in CRC and associated with poor prognosis. It may affect the occurrence and development of CRC by participating in the regulation of  T cell receptor signaling pathway and other pathways.

Key words:  Colorectal cancer, Long non-coding RNA, LINC01215, Bioinformatics, Immune infiltration