CD155 Expression Predicts Poor Prognosis in OTSCC and Correlates With TIGIT Expression and Tumor Budding

Oral tongue squamous cell carcinoma (OTSCC) is the most common malignancy of the oral cavity, characterized by aggressive clinical behavior and poor prognosis. Despite treatment advancements, patient survival rates remain unsatisfactory. CD155, an immunoglobulin superfamily member, has been implicated in tumor progression and immune evasion, with its interaction with TIGIT serving as a potential therapeutic target. This study explored the association of CD155 and TIGIT expression with tumor budding (TB) and prognosis in OTSCC.

We retrospectively reviewed the clinicopathological data of patients with primary OTSCC who underwent surgical treatment at Fukuoka University Hospital from April 2002 to December 2021. The inclusion criteria were the availability of pre-treatment tissue specimens and adherence to a consistent treatment strategy. Patients with prior chemotherapy or radiation therapy, unavailable specimens, or non-compliance with the treatment protocol were excluded. CD155 and TIGIT expression levels were assessed with immunohistochemistry assays, and TB was graded.

Overall, 35 patients with OTSCC (60% male, mean age 67.1 years) were included. The median follow-up period was 35.1 months. High-grade CD155 expression was observed in eight patients (22.9%), while high TIGIT expression was noted in 13 patients (43.3%). High TB was significantly associated with high CD155 and high TIGIT expression. Patients with high CD155 expression had significantly shorter overall survival (median 21 months vs. 36 months for CD155-low), as did patients with high TIGIT expression (median 22 months vs. 37 months for TIGIT-Low) and those with TB-High (median 20 months vs. 38 months for TB-Low).

CD155 and TIGIT are potential prognostic biomarkers and may serve as therapeutic targets in OTSCC. Our study highlights the importance of evaluating these markers to improve patient stratification and treatment approaches.