Suitability of frozen cell pellets from cytology specimens for the Amoy 9‐in‐1 assay in patients with non‐small cell lung cancer

Abstract Background The AmoyDx Pan lung cancer PCR panel (AmoyDx PLC panel) has been approved as a companion diagnostic tool for multiple anticancer agents in patients with non‐small cell lung cancer (NSCLC). However, the suitability of cytology specimens as samples for the AmoyDx PLC panel remains unclear. We evaluated the performance of frozen cell pellets from cytology specimens (FCPs) in the Amoy 9‐in‐1 assay, a preapproval assay of the AmoyDx PLC panel. Methods We retrospectively collected data of NSCLC patients enrolled in LC‐SCRUM‐Asia from the Shizuoka Cancer Center between September 2019 and May 2021. Results A total of 49 cases submitted FCPs for evaluation of oncogenic driver alterations and were assessed using Amoy 9‐in‐1 and next‐generation sequencing (NGS) assays. The success rates of DNA and RNA analyses using the Amoy 9‐in‐1 were both 100%, compared with 86% and 45%, respectively, using NGS assays. Oncogenic driver alterations were detected in 27 (55%) and 23 (47%) patients using Amoy 9‐in‐1 and NGS, respectively. No inconsistent results were observed among 19 cases in which both assays showed successful detection. In the remaining 30 cases, 10 had inconsistent results: nine oncogenic driver alterations (3 MET, 2 ALK, 2 ROS1, and 2 KRAS) were detectable only in Amoy 9‐in‐1, and one epidermal growth factor receptor (EGFR) mutation was detectable only in NGS. Conclusion FCPs can be successfully used in the AmoyDx PLC panel, with higher success rate compared with the NGS assay. The AmoyDx PLC panel may be an option in cases when insufficient tissue sample is available for the NGS assay.