LAUSR

Introduction The interaction of CD155 with its ligand, the T cell immunoreceptor with Ig and ITIM domains (TIGIT), is being studied owing to its potential to act as a target in the treatment of various solid tumors. However, the relationship between CD155 and TIGIT in colorectal cancer (CRC) prognosis is not known. We hypothesized that the TIGIT–CD155 pathway suppresses the attack of T cells on tumors, thereby affecting CRC prognosis. Methods We examined the expression of CD155 and TIGIT using immunohistochemical staining in 100 consecutive patients with CRC who underwent complete resection of ≤Stage III tumors at Wakayama Medical University Hospital between January and December 2013. We assessed the correlation between CD155 and TIGIT expressions and prognosis as well as the clinicopathological background of CD155 and TIGIT. Results Patients with high CD155 and TIGIT expressions showed worse prognosis than those with other levels of expression (p = 0.026). In multivariate analysis that also included the existing prognostic markers, high CD155 and TIGIT expressions were identified as independent poor prognostic factors. Conclusions The interaction between CD155 and TIGIT possibly plays an important role in the immunological mechanism of CRC. Therefore, it may be possible to effectively predict the postoperative prognosis of CRC by evaluating the combined expression of CD155 and TIGIT. The study findings suggest that CD155 and TIGIT can predict clinical outcomes, thereby contributing to the personalized care of CRC.