Abstract 4562: Tumor B7-H3 (CD276) expression and survival of patients with pancreatic cancer

Abstract

Abstract Background: B7-H3 (CD276) belongs to a family of immune modulators that includes PD-L1 (B7-H1 or CD274), and has been associated with tumor immunosuppression. Although several studies have reported the association of B7-H3 expression with prognosis in pancreatic cancer, the results are conflicting and inconclusive. We therefore examined the association of tumor B7-H3 expression with prognosis of pancreatic cancer. Methods: Using tissue microarrays of 150 consecutive cases of pancreatic cancer, we evaluated tumor B7-H3 expression by immunohistochemistry. We examined the prognostic association of B7-H3 expression, using the log-rank test. We also used Cox proportional hazards regression models to compute the mortality hazard ratio (HR), adjusted for covariates including pathological-stage, tumor differentiation, preoperative levels of CEA and CA19-9, and adjuvant chemotherapy. Results: Tumor B7-H3 positivity (10% of tumor cells) was observed in 99 (66%) of 150 cases of pancreatic cancer. In a log-rank test, B7-H3 positivity was associated with higher pancreatic cancer-specific mortality (P = 0.0005). In a multivariable analysis, B7-H3 positivity was independently associated with higher pancreatic cancer-specific mortality (multivariable HR = 1.82; 95% confidence interval [CI] = 1.25-2.71; P = 0.0016). When we divided immunoreactivity of B7-H3 into four scores; i.e., score 0, negative; score 1, weak; score 2, moderate; score 3, strong, the immunoreactivity scores of B7-H3 were 51 (34%), 67 (45%), 20 (13%), 12 (8%) for score 0, 1, 2, 3, respectively. In a log-rank test, higher score of B7-H3 immunoreactivity was associated with higher pancreatic cancer-specific mortality (P = 0.0014). In a multivariable analysis, higher B7-H3 immunoreactivity was independently associated with higher pancreatic cancer-specific mortality (comparing score 3 versus score 0: multivariable HR = 2.78; 95% CI = 1.38-5.25; P for trend = 0.0011). Conclusion: Tumor B7-H3 positivity and higher B7-H3 immunoreactivity are both independently associated with higher mortality of pancreatic cancer. Citation Format: Kentaro Inamura, Yusuke Yokouchi, Maki Kobayashi, Yosuke Inoue, Akio Saiura, Yutaka Takazawa, Yuichi Ishikawa. Tumor B7-H3 (CD276) expression and survival of patients with pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4562.