Expression feature and prognostic function of a novel immune checkpoint Siglec-15 in human colorectal cancer

Sialic acid-bound immunoglobulin lectin 15 (Siglec-15) plays an important role in the development of cancer. However, the association between Siglec-15 expression and clinicopathological characteristics of colorectal cancer (CRC) has not been fully investigated. In this present study, a number of bioinformatics analyses were performed to provide an overview and detailed characteristics of Siglec-15. Quantitative real-time polymerase chain reaction (qPCR), western blotting and immunohistochemistry analyses were conducted to characterize the expression of Siglec-15 in CRC. Kaplan-Meier survival and Cox regression analyses were performed to identify the prognostic parameters of CRC. The results of bioinformatics analyses revealed the expression characteristics and prognostic roles of Siglec-15 in CRC. The data of qCPR, western blotting, and IHC analyses demonstrated that the expression of Siglec-15 in CRC tissues was significantly higher than that in non-cancerous tissues. Moreover, the expression level of Siglec-15 in CRC was significantly associated with lymph node metastasis (p=0.001), TNM stage (p=0.001), and overall survival (p=0.026). COX multi-factor analysis indicated that Siglec-15 expression (p=0.023) and tumor differentiation (p=0.003) were independent prognostic factors for CRC. Collectively, the data suggested that Siglec-15 expression may serve as a novel prognostic factor and Siglec-15 might be identified as an ideal candidate for immunotherapy in CRC treatment.