Abstract 813: Doublecortin-like kinase 1 (DCLK1) and NOTCH1 pathways lead to poor prognosis in HNSCC (2020)

Abstract Introduction: Despite advancements in the field, the 5 year survival rate of Head and Neck Squamous Cell Carcinoma (HNSCC) still hovers at 60%. DCLK1 has been shown to regulate epithelial-to-mesenchymal transition (EMT) as well as serving as a cancer stem cell marker in colon, pancreatic and renal cancer. In previous studies, we showed that DCLK1 expression is associated with NOTCH pathways in HNSCC tumors obtained from publicly available databases as well as influences NOTCH signaling in HNSCC cell lines. Although it was reported that DCLK1 is associated with poor prognosis in oropharyngeal cancers and HNSCC lymph node metastasis, very little is known about the clinical implication of DCLK1 signaling in promoting HNSCC tumorigenesis. Methods and Materials: We stained 303 HNSCC and normal mucosa samples in two independent tissue microarray (TMA) assays: a commercially available US biomax HN483a and an in-house TMA built in Johns Hopkins University (JHU). TMAs were stained with antibodies against cleaved (active) NOTCH1 and DCLK1 which were previously optimized on HNSCC cell lines. The TMA tissue staining was scored by an experienced surgical pathologist. Statistical analysis was performed using Graph Pad Prism software. For overall survival (OS), Kaplan Meier Log-rank (Mantel-Cox) tests were performed. For comparison studies, we utilized the Mann Whitney test. Results: The JHU cohort consisted of 245 HNSCC samples and 13 normal tissues. Mean age of diagnosis was 59.7 year old, mean survival was 74.5 months and mean follow up time was 45.5 months. There were 35, 29, 49 and 132 patients with stages 1, 2, 3 and 4 respectively. 110 patients presented with lymph node metastasis. 47 patients were HPV+. In this TMA, DCLK1 staining was higher in tumors vs normal samples (p&amp;lt;0.05) and cleaved NOTCH1 expression followed this pattern; higher in tumors vs normal (p&amp;lt;0.0001). There was a significant correlation between the expression levels of these two proteins. The TMA was further stratified to primary tumor samples and recurrent samples as well as histological subsites of HNSCC. In primary tumors, there was a trend towards poorer OS for patients with high DCLK1 expression (p&amp;lt;0.0665), whereas in recurrent patients the OS was significantly poorer for patients with high DCLK1 expression (p&amp;lt;0.04). When analyzing HNSCC subsites, oral cavity tumors with high DCLK1 expression had poorer OS (p&amp;lt;0.0394). When we further characterized samples based on both DCLK1 and NOTCH staining, we found that the group of DCLK-/NOTCH- patients had lower mortality rate (54% vs 73%), independent of stage.Although the patients' survival data was not available for the HN468a TMA, staining on 45 HNSCC tumors indicates that 45% of the tumor samples are positive for DCLK1 compared to 90% DCLK1 negative staining in normal oral tissue. Conclusion: Overall, our results demonstrate a strong link between DCLK1 and NOTCH expression levels and poor prognosis in HNSCC. Citation Format: Esther Channah Broner, Lisa Rooper, Tejaswini Subbannayya, Aditi Chatterjee, David Sidransky, Evgeny Izumchenko. Doublecortin-like kinase 1 (DCLK1) and NOTCH1 pathways lead to poor prognosis in HNSCC [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 813.