The PD-L1 expression in surgically resected lung adenocarcinoma: Its correlations with the prognosis, driver oncogene alterations and clinicopathol...

Date 24 November 2018
Event ESMO Asia 2018 Congress
Session Poster display - Cocktail
Topics Cancer Biology
Pathology/Molecular Biology
Presenter Kazuya Takamochi
Citation Annals of Oncology (2018) 29 (suppl_9): ix139-ix142. 10.1093/annonc/mdy445
Authors K. Takamochi1, T. Hayashi2, K. Hara2, K. Suzuki1
  • 1General Thoracic Surgery, Juntendo University School of Medicine, 113-8421 - Tokyo/JP
  • 2Department Of Human Pathology, Juntendo University School of Medicine, 113-8421 - Tokyo/JP

Abstract

Background

PD-1 and PD-L1 have recently been shown to be promising immunotherapy targets and the PD-L1 expression is an important biomarker for predicting the clinical response of lung adenocarcinoma (LAD) patients.

Methods

The expression of PD-L1 in 752 surgically resected LAD specimens was evaluated by immunohistochemistry using 22C3 antibody. PD-L1 positivity was defined based on the proportion of stained tumor cells on the tissue microarray: <1% (negative), 1-49% (weakly positive), and ≥50% (strongly positive). The correlations between the PD-L1 expression and the prognosis, driver oncogene alterations and clinicopathological features were analyzed.

Results

The PD-L1 expression was negative in 576 (77%) of 752 tumors, weakly positive in 109 (14%) and strongly positive in 65 (9%). The proportion of PD-L1-positive tumors was higher in men, smokers, patients with an advanced pathological stage, tumors with a high histological grade, tumors with lymphatic, vascular or pleural invasion, tumors without EGFR mutations and tumors with KRAS mutations. The PD-L1 expression was not associated with the ALK, ROS1 and RET fusion status. The increased expression of PD-L1 was associated with poor overall survival (OS) and poor relapse-free survival (RFS) in the overall study population. The increased expression of PD-L1 was clearly associated with poor OS and RFS in patients with tumors harboringa wild-type driver oncogene (without any alterations of EGFR, KRAS, ALK, ROS1 and RET). Although this trend was observed in patients with tumors harboring driver oncogenes, it was not statistically significant.

Conclusions

LADs that positively express PD-L1 have unique clinicopathological features. The proportion of PD-L1-positive tumors differs according to the driver oncogene alterations. The expression of PD-L1 is a useful prognostic marker in surgically resected LAD .

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

Kazuya Takamochi.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.