Open AccessPD‐L1 expression in ROS1 ‐rearranged non‐small cell lung cancer: A study using simultaneous genotypic screening of EGFR , ALK , and ROS1
Author(s) -
Lee Jongmin,
Park Chan Kwon,
Yoon HyoungKyu,
Sa Young Jo,
Woo In Sook,
Kim Hyo Rim,
Kim Sue Youn,
Kim TaeJung
Publication year - 2019
Publication title -
thoracic cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 28
eISSN - 1759-7714
pISSN - 1759-7706
DOI - 10.1111/1759-7714.12917
Subject(s) - ros1 , medicine , genotyping , lung cancer , fluorescence in situ hybridization , adenocarcinoma , oncology , genotype , cancer research , immunohistochemistry , cancer , gene , genetics , biology , chromosome
Background The aim of the current study was to investigate the prevalence and clinicopathologic characteristics of ROS1 ‐rearranged non‐small cell lung cancer (NSCLC) in routine genotypic screening in conjunction with the study of PD‐L1 expression, a biomarker for first‐line treatment decisions. Methods Reflex simultaneous genotypic screening for EGFR by peptide nucleic acid clamping, and ALK and ROS1 by fluorescence in situ hybridization (FISH) was performed on consecutive NSCLC cases at the time of initial pathologic diagnosis. We evaluated genetic aberrations, clinicopathologic characteristics, and PD‐L1 tumor proportion score (TPS) using a PD‐L1 22C3 assay kit. Results In 407 consecutive NSCLC patients, simultaneous genotyping identified 14 (3.4%) ROS1 and 19 (4.7%) ALK rearrangements, as well as 106 (26%) EGFR mutations. These mutations were mutually exclusive and were found in patients with similar clinical features, including younger age, a prevalence in women, adenocarcinoma, and advanced stage. The PD‐L1 assay was performed on 130 consecutive NSCLC samples. High PD‐L1 expression (TPS ≥ 50%) was observed in 29 (22.3%) tumors. PD‐L1 expression (TPS ≥ 1%) was significantly associated with wild type EGFR , while ROS1 rearrangement was associated with high PD‐L1 expression. Of the 14 cases with ROS1 rearrangement, 12 (85.7%) showed PD‐L1 expression and 5 (35.7%) showed high PD‐L1 expression. Conclusion In the largest consecutive routine Asian NSCLC cohort analyzed to date, we found that high PD‐L1 expression frequently overlapped with ROS1 rearrangement, while it negatively correlated with EGFR mutations.