The expression of PD-L1 protein as a prognostic factor in lung squamous cell carcinoma

Kazuki Takada, Tatsuro Okamoto, Gouji Toyokawa, Yuka Kozuma, Taichi Matsubara, Naoki Haratake, Takaki Akamine, Shinkichi Takamori, Masakazu Katsura, Fumihiro Shoji, Yoshinao Oda, Yoshihiko Maehara

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)

Abstract

Background Programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway-targeted immunotherapy has become the standard option of care in the management of lung cancer. The expression of the PD-L1 protein in lung cancer is expected to be a prognostic factor or to predict the response to PD-1-blocking antibodies. However, the association between PD-L1 positivity and the clinicopathological features and patient outcomes in lung squamous cell carcinoma (SCC) remains unclear because the definitive cut-off value for the expression of PD-L1 protein remains to be established. Materials and methods The expression of PD-L1 protein in 205 surgically resected primary lung SCC patients was evaluated by immunohistochemistry with the antibody clone SP142. We generated a histogram to show the proportion of PD-L1-positive carcinoma cells, and set the cut-off values as 1%, 5%, 10% and 50%. Moreover, we examined the proliferative capacity of these tumors using Ki-67 immunohistochemistry. Results The samples from 106 (51.7%), 72 (35.1%), 61 (29.7%) and 37 (18.0%) patients were positive for the expression of PD-L1 protein at cut-off values of 1%, 5%, 10% and 50%, respectively. Fisher's exact test showed that, for almost all of the factors, PD-L1 positivity was not associated with the clinicopathological features with any of the four cut-off values. Univariate and multivariate survival analyses revealed that the PD-L1-positive patients only had a poorer prognosis than the PD-L1-negative patients at the 1% cut-off value. The Ki-67 labeling index in the PD-L1-positive patients was higher than that in the PD-L1-negative patients. Conclusions The expression of PD-L1 protein was associated with a poor prognosis in lung SCC patients. The 1% cut-off value for PD-L1 might become a better predictive marker than the other cut-off values.

Original languageEnglish
Pages (from-to)7-15
Number of pages9
JournalLung Cancer
Volume104
DOIs
Publication statusPublished - Feb 1 2017

All Science Journal Classification (ASJC) codes

  • Oncology
  • Pulmonary and Respiratory Medicine
  • Cancer Research

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