PD-L1 expression in squamous-cell carcinoma and adenocarcinoma of the lung
Article Category: Research Article
Online veröffentlicht: 14. Sept. 2017
Seitenbereich: 357 - 362
Eingereicht: 27. Apr. 2017
Akzeptiert: 09. Aug. 2017
DOI: https://doi.org/10.1515/raon-2017-0037
© 2017 Urska Janzic, Izidor Kern, Andrej Janzic, Luka Cavka, Tanja Cufer
This work is licensed under the Creative Commons Attribution 4.0 International License.
Background
With introduction of immunotherapy (IT) into the treatment of advanced non-small-cell lung cancer (NSCLC), a need for predictive biomarker became apparent. Programmed death ligand 1 (PD-L1) protein expression is most widely explored predictive marker for response to IT. We assessed PD-L1 expression in tumor cells (TC) and immune cells (IC) of squamous-cell carcinoma (SCC) and adenocarcinoma (AC) patients.
Patients and methods
We obtained 54 surgically resected tumor specimens and assessed PD-L1 expression by immunohistochemistry after staining them with antibody SP142 (Ventana, USA). Clinicopathological characteristics were acquired from the hospital registry database. Results were analyzed according to cut-off values of ≥ 5% and ≥ 10% of PD-L1 expression on either TC or IC.
Results
29 (54%) samples were AC and 25 (46%) were SCC. PD-L1 expression was significantly higher in TC of SCC compared to AC at both cut-off values (52% vs. 17%, p = 0.016 and 52% vs. 14%, p = 0.007, respectively) no difference in PD-L1 expression in IC of SCC and AC was found. In AC alone, PD-L1 expression was significantly higher in IC compared to TC at both cut-off values (72% vs. 17%, p < 0.001 and 41% vs. 14%, p = 0.008, respectively), while no significant difference between IC and TC PD-L1 expression was revealed in SCC.
Conclusions
Our results suggest a significantly higher PD-L1 expression in TC of SCC compared to AC, regardless of the cut-off value. PD-L1 expression in IC is high in both histological subtypes of NSCLC, and adds significantly to the overall positivity of AC but not SCC.