149P - PD-L1 expression patterns in the metastatic tumors to the lung: A comparative study with the primary non-small cell lung cancer

Date 07 May 2017
Event ELCC 2017
Session Poster Display Session
Topics Thoracic Malignancies
Non-Small Cell Lung Cancer
Presenter Zoran Gatalica
Citation Annals of Oncology (2017) 28 (suppl_2): ii52-ii55. 10.1093/annonc/mdx094
Authors Z. Gatalica1, J. Senarathne1, S. Vranic2
  • 1Caris Life Sciences, 85040 - Phoenix/US
  • 2Pathology, Clinical Centre of Sarajevo University, 71000 - Sarajevo/BA

Abstract

Background

Immune check point inhibitors (anti-PD-1/PD-L1) therapy has revolutionized cancer treatment of several, advanced and chemotherapy resistant malignancies. PD-L1 expression on tumor (TC) and/or inflammatory cells (IC) has been associated with a more favorable therapy response. We compared PD-L1 distribution in a large cohort of advanced tumors metastatic to the lungs and compared it with the primary lung non-small cell carcinomas (NSCLC).

Methods

The study groups included 176 metastatic cancers and 81 NSCLC. Expression of PD-L1 was assessed using immunohistochemistry (SP142, Ventana). PD-L1 positivity was defined as 2+ intensity at ≥ 5% in TC or IC cells. All cases were further stratified into 4 categories based on the expression presence or absence of PD-L1 expression on tumor or IC cells. PD-L1 expression was correlated with total mutational load (TML) measured in tumors using NGS.

Results

Overall TC PD-L1 positivity was significantly higher in NSCLC compared with metastatic tumors (28% vs. 14%, p = 0.009) although some metastatic cancers (e.g. triple-negative breast and head/neck carcinomas, melanoma) exhibited higher TC PD-L1 expression. In contrast, overall IC PD-L1 expression was predominantly observed in metastatic tumors (28% vs. 0%, p < 0.001). The IC PD-L1 expression ranged from 0% for metastatic renal cell carcinomas to 36-38% in the metastatic breast and colon carcinomas and melanoma. Consequently, the stratification based on PD-L1 distribution (TC vs. IC), resulted in significantly different patterns between the primary and metastatic tumors (p < 0.001, Table). Mean TML (±SD) for NSCLC (10±5.6) differed significantly from metastatic carcinomas from other sites (6.6±2.7) (p = 0.013).

Conclusions

Our study indicate that a substantial proportion of metastatic tumors to the lung exhibit PD-L1 expression on either tumor or inflammatory (immune) cells and are potentially amenable for the treatment with immune check point inhibitors.rnTable: 149Prn

rnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrnrn
HistotypesTME categories (PD-L1 expression)Total
TC+/IC+TC-/IC-TC+/IC-TC-/IC+
NSCLC05823081
Metastatic tumors81111641176
Total81693941257
rn

Clinical trial identification

Legal entity responsible for the study

None

Funding

Caris Life Sciences

Disclosure

Z. Gatalica: Employee of Caris Life Sciences. J. Senarathne: Jude Senarathne is an employee of Caris Life Sciences. S. Vranic: Received honoraria from Caris Life Sciences.