Abstract 5067: Exploring the genomic landscape of de novo neuroendocrine prostate cancer: Insights for innovative therapies from spatial gene expression analysis

Abstract

Abstract Introduction & Objectives Neuroendocrine prostate cancer (NEPC) accounts for less than 1% of all prostate cancers but has a worse prognosis than androgen receptor-positive prostate adenocarcinoma (ARPC). Rare cases exist where both de novo NEPC and ARPC are found in the same tissue sample. Our study examines one such unique case: a 78-year-old male treated at Ehime University Hospital who was diagnosed with both ARPC and adjacent de novo metastatic NEPC. This case provides an excellent opportunity for studying gene expression in these two types of prostate cancer. Materials & Methods We used Visium CytAssist Spatial Gene Expression technology from 10x Genomics to analyze formalin-fixed, paraffin-embedded (FFPE) tissue samples from this unique patient. Results We observed elevated expression levels of specific neuroendocrine markers like PEG10, DLL3, NCAM1, SYP, and CHGA in de novo NEPC regions. In contrast, androgen receptor markers such as KLK3, ACPP, TMPRSS2, and NKX3.1 were more prevalent in ARPC areas. Furthermore, genes like Chek1, BRCA1/2, TOP2A, and FANCA were also elevated in NEPC, suggesting that PARP and TOP2 inhibitors could be effective. Expression levels of Rbfox3 and SFRTM2 were lower in NEPC areas, implying possible roles in epithelial-mesenchymal transition (EMT) and Wnt signaling pathways. Additionally, fibrotic markers like HGF, HMOX1, ELN, and GREM1 were upregulated, suggesting that de novo NEPC tumors might be 'immune cold,' thus requiring treatments to boost the effectiveness of immune checkpoint inhibitors. Conclusion The data from additional cases could open the door for new treatment options for NEPC and improve survival rates for castration-resistant prostate cancer patients. Our research serves as a pioneering application of Visium CytAssist on FFPE samples and is the first to examine gene expression in both ARPC and de novo NEPC. A subset of these findings was published in the International Journal of Molecular Science (IJMS) in May 2023. Citation Format: Ryuta Watanabe, Noriyoshi Miura, Mie Kurata, Riko Kitazawa, Tadahiko Kikugawa, Takashi Saika. Exploring the genomic landscape of de novo neuroendocrine prostate cancer: Insights for innovative therapies from spatial gene expression analysis [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 5067.