Background: STING is an innate immune sensor for cytosolic DNA. The activation of STING signaling is indispensable in Type I interferon response and the evocation of anticancer immune response by CD8+ T-cells. The aim of this study is to characterize intratumoral STING expression pattern and its clinical implication in colorectal cancer (CRC). Methods: We analyzed STING and CD8 expression in 225 CRC patients who underwent surgical resection. Clinicopathologic variables and survival outcomes were analyzed according to STING expression level. Results: Distinct STING expression was observed in tumor specimens of CRCs. Patients with higher STING expression seemed to have early stage cancer (P = 0.001) with increased intratumoral CD8+ T-cell infiltration (P < 0.001), and less frequent lymphovascular invasion (P = 0.02). Compared to CRC patients with lower STING expression, those with higher STING expression had longer overall survival (P < 0.001) and recurrence-free survival (P < 0.001). The Cox proportional hazard model, adjusted for age, stage, and CD8+ T-cells, revealed that higher STING expression is an independent prognostic factor for a better overall survival (P = 0.012, hazard ratio 0.573, 95% CI 0.370 – 0.886). Conclusion: We have confirmed the distinct STING expression in CRC and demonstrated its independent prognostic value for the survival outcome, thereby suggesting the intratumoral STING expression as a potential immune biomarker for CRC.

Citation Format: Hongjae Chon, Chan Kim. STING, an immune biomarker for colorectal cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A061.

©2019 American Association for Cancer Research.
2019
American Association for Cancer Research.