Abstract 2570: Gastric cancer with high neuron infiltration was associated with enhanced epithelial-to-mesenchymal transition, angiogenesis and poor clinical outcomes
Authors: Chida Kohei , Oshi Masanori , Roy Arya Mariam , Arima Jun , Sharma Pia , Mann Gabriella Kim , Endo Itaru , Hakamada Kenichi , Takabe Kazuaki 
Published: March 2024

Abstract
Introduction: Neurons within the tumor microenvironment of gastric cancer (GC), as identified through immunohistochemistry, have been reported to be associated with worse overall survival (OS) of GC patients. However, histology-based analyses have limitations in quantifying nerve cells and investigating the underlying biology. Thus, we aim to study the clinical significance of intratumoral nerve cells in GC using computational deconvolution of transcriptomes from bulk tumors.
Methods: Total of 807 GC patients from two independent cohorts (TCGA; n = 375, GSE84437; n = 432) were included, encompassing both clinical and transcriptomic profiles. The neuron infiltration fraction was determined using the xCell algorithm.
Results: GC with high neuron infiltration was associated with high expressions of neurotransmitter receptors; beta-adrenaline, dopamine, muscarinic acetylcholine, and neurokinin receptors in TCGA cohort (all p &lt; 0.02). It was associated with reduced mutation rate and increased intratumoral heterogeneity (all p ≦ 0.002), as well as less immune response; interferon-alpha and interferon-gamma, and with low infiltration of immune cells; CD4 memory, T-helper 1, M1 and M2 macrophages, and NK cells (all p ≦ 0.02). Further, neuron highly infiltrated GC enriched Epithelial-to-Mesenchymal Transition and Angiogenesis gene sets and had higher lymphatic and microvessel endothelial cells and pericyte infiltrations (all p ≦ 0.001). Conversely, GC with high neuron infiltration showed an inverse relationship with cell proliferation-related gene sets; E2F Targets, G2M Checkpoint, and MYC Targets v1 and v2, and had lower Ki67 gene expression (FDR &lt; 0.25 and p &lt; 0.001, respectively). High neuron infiltration in GC was associated with worse patient OS in TCGA cohort, which was validated in GSE84437 cohort (both p &lt; 0.05). It was an independent prognostic factor of OS in both univariate and multivariate Cox-regression analysis in the TCGA cohort (hazard ratio [HR]: 1.46; 95% confidence interval [CI]: 1.01 to 2.12; p = 0.045 and [HR]:1.54; 95% CI: 1.05 to 2.26; p = 0.026).
Conclusion: Our research indicates that high infiltration of neurons in GC correlates with high expressions of neurotransmitter receptors, high intratumoral heterogeneity, less immune response and immune cell infiltrations, and less cell proliferation. It enriched EMT and angiogenesis which may explain its association with worse patient survival.
Citation Format: Kohei Chida, Masanori Oshi, Arya Mariam Roy, Jun Arima, Pia Sharma, Gabriella Kim Mann, Itaru Endo, Kenichi Hakamada, Kazuaki Takabe. Gastric cancer with high neuron infiltration was associated with enhanced epithelial-to-mesenchymal transition, angiogenesis and poor clinical outcomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2570.