Abstract 5177: Primary tumor induces lymphangiogenesis and immune suppression in sentinel lymph nodes

Abstract

Abstract The main factor that affects the prognosis of patients with squamous cell carcinoma of the head and neck (SCCHN) is regional lymph node metastases, which usually spreads first to the sentinel lymph nodes (SLNs). Recent studies using animal models have demonstrated that tumor cells can induce lymphangiogenesis in SLNs before metastasizing. In this study, we investigated the association of SLN lymphangiogenesis with the status of primary tumors. Moreover, the immunological status of SLNs was also examined. The expression of lymphatic-specific markers, including VEGFR-3, Prox-1, and LYVE-1 in 23 metastasis-negative SLNs obtained from 10 patients with SCCHN was investigated using quantitative real-time RT-PCR. Moreover, primary tumors obtained from patients were evaluated for the expression of VEGF-A, -C, and -D by immunohistochemistry. The level of LYVE-1 expression in SLNs was significantly higher than in control lymph nodes from patients with non-cancerous diseases. Moreover, SLNs from patients with VEGF-C-positive tumor showed a significantly higher expression of VEGFR-3 than those from patients with VEGF-C-negative tumor. VEGFR-3 is expressed mainly in lymphatic endothelium but also in a subset of antigen-presenting cells including immature dendritic cells (DCs), therefore; we furthermore examined the infiltration of DCs into SLN by immunohistochemistry. Interestingly, S-100+ and CD1a+ immature DCs infiltrated significantly into SLNs compared to non-SLNs in patients with SCCHN, suggesting that predominant migration of immature DCs, which suppress T-cell activation and support regulatory T cell development, would contribute to inhibit rather than develop anti-tumor immunity. Our findings suggest that primary tumor actively induces lymphangiogenesis in SLNs prior to the onset of metastases, and where tumor-derived VEGF-C plays an important role. Moreover, active lymphangiogenesis may concomitantly lead to down-regulation of SLN immunity. Thus, both lymphangiogenesis and immune suppression in SLNs are likely the basis of its susceptibility to tumor metastases. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5177. doi:10.1158/1538-7445.AM2011-5177