PD-L1 expression in lung adenocarcinoma harboring EGFR mutations or ALK rearrangements

Yasuto Yoneshima, Kayo Ijichi, Satoshi Anai, keiichi ota, Kohei Otsubo, Eiji Iwama, Kentaro Tanaka, Yoshinao Oda, Yoichi Nakanishi, Isamu Okamoto

Research output: Contribution to journalArticlepeer-review

74 Citations (Scopus)


Objectives: Expression of programmed cell death–ligand 1 (PD-L1) has been associated with clinical outcome of programmed cell death–1 (PD-1) pathway blockade in non–small cell lung cancer (NSCLC). The PD-L1 IHC 22C3 pharmDx assay, the only companion diagnostic for pembrolizumab therapy, has revealed that ∼30% of all NSCLCs express PD-L1 at a high level. The frequency of high PD-L1 expression in NSCLCs with known driver oncogenes has remained unclear, however. Materials and methods: We retrospectively evaluated PD-L1 expression with the 22C3 assay in tumor tissue of 80 lung adenocarcinoma patients including 71 with EGFR mutations and 9 with ALK rearrangements, all of whom were treated with corresponding tyrosine kinase inhibitors (TKIs). Results: Of the 80 tumors analyzed, 26 (32.5%) had a PD-L1 tumor proportion score (TPS) of 1%–49% and 9 (11.3%) had a PD-L1 TPS of ≥50%; 35 (43.8%) thus had a PD-L1 TPS of ≥1%. Of the 71 tumors with EGFR mutations, 23 (32.4%) had a PD-L1 TPS of 1%–49% and 7 (9.9%) had a PD-L1 TPS of ≥50%. A PD-L1 TPS of ≥1% was not associated with any clinical characteristic examined. Progression-free survival on initial TKI treatment was significantly poorer for patients with a PD-L1 TPS of ≥1% than for those with a PD-L1 TPS of <1% (p =.016). Conclusions: A subset of patients with EGFR mutations or ALK rearrangements had a PD-L1 TPS of ≥50%. Prospective studies are thus warranted to examine the efficacy of PD-1/PD-L1 inhibitors in such patients.

Original languageEnglish
Pages (from-to)36-40
Number of pages5
JournalLung Cancer
Publication statusPublished - Apr 2018

All Science Journal Classification (ASJC) codes

  • Oncology
  • Pulmonary and Respiratory Medicine
  • Cancer Research


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