5P - PD-L1 expression in NSCLC

Date 15 April 2016
Event European Lung Cancer Conference 2016 (ELCC) 2016
Session Poster lunch
Topics Lung and other Thoracic Tumours
Pathology/Molecular Biology
Translational Research
Presenter Urska Janzic
Citation Journal of Thoracic Oncology (2016) 11 (supplement 4): S57-S166. S1556-0864(16)X0004-4
Authors U. Janzic1, I. Kern2, A. Janzic3, L. Cavka4, T. Cufer1
  • 1Department Of Medical Oncology, University Clinic Golnik, 4204 - Golnik/SI
  • 2Department Of Pathology, University Clinic Golnik, 4204 - Golnik/SI
  • 3Chair Of Social Pharmacy, Faculty of Pharmacy, University of Ljubljana, Slovenia, 1000 - Ljubljana/SI
  • 4Department Of Medical Oncology, Institute of Oncology Ljubljana, Ljubljana/SI

Abstract

Background

Immunotherapy (IT) with checkpoint inhibitors is becoming a standard treatment for NSCLC. Since only 30% of unselected patients respond to IT, there is a need for a predictive biomarker, especially in adenocarcinomas. So far PD-L1 was the most promising marker. Therefore, we assessed the expression of PD-L1 in tumor cells (TC) and in immune cells (IC) of lung adenocarcinomas (AC) and squamous-cell carcinomas (SCC).

Methods

We analyzed whole FFPE tumor tissue sections of 54 consecutive NSCLC patients treated at one academic hospital. PD-L1 expression in TCs and ICs was determined by immunohistochemistry using antibody SP142 (Ventana, USA). The results were statistically analyzed for two preplanned cut-off values, namely 5% and 10% of PD-L1 positivity in either TCs or ICs, regardless of the intensity. Baseline patients' characteristics were obtained from the hospital registry database.

Results

There were 29 (54%) AC and 25 (46%) SCC; the mean age was 62.4 years, 34 (63%) were male, most of them current or ex-smokers 46 (85%). TC PD-L1 positivity was significantly higher in SCC vs. AC, at both 5% and 10% cut-offs (52% vs. 17%, p = 0.016 and 52% vs. 14%, p = 0.007, respectively) while IC PD-L1 positivity was similar in SCC and AC, at both cut-offs (76% vs. 72%, p = 1 and 64% vs. 41%, p = 0.166, respectively). PD-L1 positivity was significantly higher in IC compared to TC in AD but not in SCC, regardless the cut-off value. 5PT1 Table: PD-L1 positivity according to histology and different cut-offs

 NPD-L1 >5%PD-L1 >10%
  TC or ICN (%)TCN (%)IC N (%)p (TC vs IC)TC or IC N (%)TC N (%)IC N (%)p (TC vs IC)
Total5443 (80)18 (33)40 (74) 31 (57)17 (31)28 (52) 
AC2921 (72)5 (17)21 (72)

Conclusions

PD-L1 positivity is significantly higher in SCC compared to AC when looking only at TC and not at IC or combination. PD-L1 positivity in IC, which is highly positive in both histologic subtypes, adds to the overall positivity of AC but not SCC. There is no significant difference in IC PD-L1 positivity between SCC and AC, however by lowering the cut-off value the share of PD-L1 positive AC samples increases substantially, mostly due to IC positivity.

Clinical trial identification

Legal entity responsible for the study

University Clinic Golnik

Funding

University Clinic Golnik

Disclosure

All authors have declared no conflicts of interest.