Premium
Programmed cell death ligand 1 expression in cytologic and surgical non–small cell lung carcinoma specimens from a single institution: Association with clinicopathologic features and molecular alterations
Author(s) -
Mei Ping,
Shilo Konstantin,
Wei Lai,
Shen Rulong,
Tonkovich Dena,
Li Zaibo
Publication year - 2019
Publication title -
cancer cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.29
H-Index - 57
eISSN - 1934-6638
pISSN - 1934-662X
DOI - 10.1002/cncy.22140
Subject(s) - medicine , kras , pathology , immunohistochemistry , lung cancer , biopsy , cytology , carcinoma , fine needle aspiration , cancer , colorectal cancer
Background Programmed cell death ligand 1 (PD‐L1) expression by the 22C3 pharmDx companion assay has been validated in surgical specimens to support pembrolizumab treatment decisions for patients with non–small cell lung carcinoma (NSCLC). The aims of this study were 1) to assess the adequacy of cytologic specimens for PD‐L1 evaluation and 2) to explore correlations of PD‐L1 expression with clinicopathologic and molecular features. Methods The study cohort included 100 cytology specimens (fluid [n = 28] and fine‐needle aspiration [n = 72]) and 165 surgical specimens (biopsy [n = 138] and resection [n = 27]). The PD‐L1 immunohistochemistry 22C3 assay and staining assessment were performed according to the manufacturer's instructions. PD‐L1 expression was correlated with patients' demographics, pathologic characteristics, and molecular alterations. Results One hundred forty‐two specimens (53.6%) were positive for PD‐L1 expression (≥1%). No statistically significant difference in PD‐L1 expression was identified between cytologic (56.0%) and surgical specimens (52.1%). Seventy‐four of 190 tested cases (38.9%) had genetic alterations. PD‐L1 positivity was significantly more prevalent in cases with genetic alterations than in cases without genetic alterations. Furthermore, both PD‐L1 positivity and high PD‐L1 expression (≥50%) had statistically significant associations with Kirsten rat sarcoma viral oncogene homolog ( KRAS ) mutations. PD‐L1 expression had no significant association with histologic phenotypes or other clinicopathologic features. Conclusions The data indicate that cytologic specimens are comparable to surgical specimens for PD‐L1 evaluation. The association of PD‐L1 expression with KRAS mutations may have clinical relevance in selecting patients with NSCLC for immunotherapy.