Abstract 2976: Establishment of organoids derived from patients with advanced thoracic malignancies

Background: In the past decade, three-dimensional organoid culture derived from various tumors has been applied to cancer research. Compared to the conventional two-dimensional cell culture, organoid culture recapitulates in vivo system and furthermore, its high establishment rate may hold the potential to help decision-making for precision medicine. However, it remains challenging to establish organoids from advanced thoracic malignancies due to a limited amount of biopsy specimens. Here, we report the attempt to establish organoids from endoscopic biopsy specimens and pleural effusions in patients with advanced thoracic malignancies Methods: Organoid culture was attempted using biopsy specimens or pleural effusions from patients who underwent transbronchial biopsy, thoracoscopic biopsy or thoracentesis. After confirming the presence of malignant cells by rapid on-site evaluation, biopsy specimens were digested with collagenase and dispase at 37°C followed by being harvested and cultured in Matrigel. As for pleural effusions, mononuclear cells were isolated by ficoll density gradient centrifugation and CD45+ cells were depleted using anti-CD45 magnetic beads. Then, the resultant cells were cultured in Matrigel. Next-generation sequencing was performed to confirm cancer-related somatic mutations using Ion PGM system. Cell viability assay was performed by resazurin assay. Results:142 patients were registered in the study between May 2019 and October 2020 at Wakayama Medical University. Fifty-one cases were excluded because of negative diagnosis for malignancy, retraction of the consent or risk of bleeding associated with biopsy. We attempted to culture organoids using 98 samples from 91 patients. The types of malignancies were as follows: non-small cell lung cancers (NSCLC)/SCLC/others, 80/8/3. A total of 33 organoids were successfully cultured with sustainable proliferation and 16 were successfully cryopreserved. Established organoids were confirmed to harbor the same mutations as detected by clinical testing with tissue samples and to form tumors in a xenotransplantation model. HLCO-75, established from pleural effusion at disease progression after osimertinib treatment was genotyped and found to gain ERBB2 V777L mutation in exon 20 in addition to original EGFR L858R mutation. Marked growth-inhibitory effect by poziotinib, a HER2 tyrosine kinase inhibitor with IC50 value 6 nM was observed whereas not by TAS6417, another EGFR/HER2 exon 20 inhibitor, suggesting the potential of organoid culture for decision-making in cancer precision medicine. Conclusion: Our results suggest that organoid culture is feasible from small biopsy specimens and these organoids could be applied for personalized medicine. Citation Format: Jun Oyanagi, Yasuhiro Koh, Koichi Sato, Masanori Tanaka, Katsuyuki Furuta, Takeya Sugimoto, Ryota Shibaki, Shunsuke Teraoka, Daichi Fujimoto, Nahomi Tokudome, Hiroaki Akamatsu, Atsushi Hayata, Atsushi Hayata, Yuichi Ozawa, Hiroki Ueda, Nobuyuki Yamamoto. Establishment of organoids derived from patients with advanced thoracic malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2976.