485 Comparative gene expression and mutational profiling of neuroendocrine tumors and neuroendocrine carcinomas in relation to clinical outcomes

Objectives/Goals: Neuroendocrine malignancies are heterogeneous cancers with varied clinical outcomes, yet the molecular landscape driving this heterogeneity has not been fully characterized. Here, we investigate the gene expression and mutational profiles of neuroendocrine malignancies to better understand the underlying biology and therapeutic targets. Methods/Study Population: Patients with neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs) treated at Cleveland Clinic (2000–2022) with molecular profiling (n = 66) were identified. Mutational and gene expression profiles were abstracted from electronic health records (EHR). Clinico-pathological characteristics and overall survival (OS) were obtained from EHR. Statistical analyses were performed by R v.4.0.5 and R package Limma for differential gene expression, as well as Chi-square, Fisher’s exact, and Wilcoxon rank sum tests. Results/Anticipated Results: The cohort consisted of 38 cases with NEC, 18 NET g3, and 10 NET g1/2. EZH2 and cyclin E1 were differentially over-expressed in NEC vs. NET (p < 0.05), while PTEN and MSLN were differentially under-expressed in NEC vs. NET (p < 0.005). Several recurrent alterations co-segregated with aggressive histology (NEC vs. NET): TP53 (p 60. Also, there was no difference in gene expression profiles between the two age groups among NETs or NECs. Discussion/Significance of Impact: This study explores the molecular landscape of NETs and NECs, revealing distinct gene expression and mutation profiles related to clinical outcomes. High expressions of cyclin D1 and EGFR were significantly associated with improved 2-year OS in NECs, highlighting potential therapeutic targets. Future studies are needed to validate these findings.