The interplay between PD-L1 and vimentin in NSCLC patients: An exploratory analysis.

Abstract

e20688 Background: The immune modulation is emerging as a key strategy in non-small cell lung cancer (NSCLC) patients management. PD-L1 has been the only biomarker validated for immunotherapy but it holds many limitations. Vimentin is one of the marker for epithelial-to-mesenchymal transition (EMT), a biological process which favors immune escape. We explored two issues: the correlation between PD-L1 and Vimentin expression in NSCLC samples and the prognostic value of PD-L1 and vimentin concordance in NSCLC patients. Methods: We collected all the NSCLC samples evaluable for both PD-L1 and Vimentin and recorded the relative available clinical and survival data, if written informed consent was present. PD-L1 and Vimentin were retrospectively assessed through immunohistochemistry (IHC) by using prediluted antibodies clones SP263 (Ventana Medical Systems, Tucson, AZ, USA) and anti Vimentin V9 (Ventana Medical Systems) on Benchmark XT Platform (Ventana Medical Systems). Biomarker expression was detected and semiquantitatively quantified as the percentage of immunopositive tumor cells on the total of tumor cells. We correlated PD-L1 and Vimentin expression through linear regression. We compared survival of patients with both PD-L1 and Vimentin 0% and all the others via Kaplan-Meier method by using MedCalc software version 18.11.3. Results: Ninety-nine samples underwent PD-L1 and Vimentin IHC analysis. A weak positive statistically significant correlation was found between the 2 biomarkers (r = 0.41; p < 0.001). For 40 patients survival data (from first NSCLC diagnosis) were available. Survival analysis showed that PD-L1 and Vimentin negative patients (n = 12) experienced not statistically significant longer survival (HR = 0.35; 95%CI: 0.08-1.51; p = 0.16). Conclusions: These preliminary findings suggest that an interplay can exist between PD-L1 and vimentin in NSCLC, but analysis in a wider population is necessary. Studies on the significance of this interplay for immunotherapy efficacy should be designed.