Abstract 3147: Identification of developmental endothelial locus-1 on circulating extracellular vesicles as a novel biomarker for early breast cancer detection

Purpose: Currently, there are no molecular biomarkers for the early detection of breast cancer (BC). This study focused on identifying surface proteins found on circulating extracellular vesicles (EVs) for detecting early-stage BC. Experimental Design: Circulating EVs, isolated from the plasma of 10 patients with BC (stages I and II), and 5 healthy controls, were analyzed using LC-MS/MS. Developmental endothelial locus-1 protein (Del-1) was selected as a candidate biomarker. Two different enzyme-linked immunosorbent assays (ELISAs) were used to measure Del-1 in plasma samples from healthy controls (n = 81), patients with BC (n = 269), BC patients after surgical resection (n = 50), patients with benign breast tumors (n = 64), and patients with non-cancerous diseases (n = 98), in two cohorts. Results: Plasma Del-1 levels were significantly higher (P < 0.0001) in patients with BC than in all controls and returned to almost normal after tumor removal. The diagnostic accuracy of Del-1 was area under the curve (AUC), 0.961 [95% CI, 0.924-0.983], sensitivity of 94.70% and specificity of 86.36% in test cohort, and 0.968 [0.933-0.988], 92.31% and 86.62% in validation cohort for early-stage BC by one type of ELISA. Furthermore, Del-1 maintained diagnostic accuracy for patients with early-stage BC using the other type of ELISA (0.946 [0.905-0.972], 90.90%, and 77.14% in the test cohort; 0.943 [0.900-0.971], 89.23%, and 80.99% in the validation cohort). Conclusions: Del-1 on circulating EVs is a promising marker to improve identification of patients with early-stage BC and distinguish BC from benign breast tumors and non-cancerous diseases. Citation Format: Pyong-Gon P. Moon, Jeong-Eun Lee, Young-Eun Cho, Soo Jung Lee, Jin Hyang Jung, Yee Soo Chae, Han-Ik Bae, Young-Bum Kim, In-San Kim, Hoyong Park, Moon-Chang Baek. Identification of developmental endothelial locus-1 on circulating extracellular vesicles as a novel biomarker for early breast cancer detection. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3147.