Tumor Cell JAGGED-1 Promotes Lymph Node Metastasis and Predicts Recurrence in Lymph Node Positive Breast Cancer Patients [MDA231LN_JAG1_KO1_KO2]

Purpose: Lymph node invasion is a hallmark of breast cancer disease progression, but current treatment strategies lack guidance from lymph node biomarkers. We investigated JAGGED1 (JAG1) as a promoter of lymph node metastasis and a prognostic biomarker in metastatic lymph node specimens. Experimental Design: We used mouse models to assess the role of JAG1 expression in human and mouse breast cancer cells on lymphovascular invasion, lymph node metastatic potential, transcriptional profiles, and tumor interactions with lymphatic endothelium. We examined breast and lymph node samples from 284 breast cancer patients to determine the correlative and prognostic value of tumoral JAG1 expression in the lymph node. Results: In matched human breast tumor and lymph node samples, tumor cells that invaded lymph nodes showed higher JAG1 expression than their associated primary tumors (P value < 0.0001). In multiple models, breast cancer cells with high JAG1 expression showed increased lymphovascular invasion, lymph node metastasis, lymph node metastatic outgrowth, and migration through lymphatic endothelium. Transcriptomic analysis indicated that tumoral JAG1 regulates both juxtacrine and paracrine signaling pathways that induce inflammatory and pro-metastatic genes in lymphatic endothelium. When examining patients with identical surgical treatments, patients with lymph node JAG1 H-scorelow showed increased 5-year recurrence free survival rates than patients with lymph node JAG1 H-scorehi (87% vs 70%, P=0.016). Conclusions: JAG1 expression promotes lymphovascular invasion and lymph node metastasis in murine models. In patients, high expression of JAG1 in tumor cells in lymph node metastases predicts reduced recurrence free survival.