PD-L1 Expression in Unresectable Locally Advanced or Metastatic Skin Squamous Cell Carcinoma Treated with Anti-Epidermal Growth Factor Receptor Agents

Stefano Cavalieri, Federica Perrone, Massimo Milione, Alba Bianco, Salvatore Alfieri, Laura D. Locati, Cristiana Bergamini, Carlo Resteghini, Donata Galbiati, Francesca Platini, Lisa Licitra, Paolo Bossi

Research output: Contribution to journalArticle


Background: Recurrent or metastatic (R/M) skin squamous cell carcinoma (sSCC) not amenable of surgery or irradiation may benefit from systemic therapies. Epidermal growth factor receptor (EGFR) inhibitors and, more recently, immune checkpoint blockers (ICBs) showed activity in R/M sSCC. In this study, we aimed at exploring the possible role of PD-L1 expression in predicting response to anti-EGFR agents. Methods: Patients affected by R/M sSCC, treated with pan-HER inhibitor dacomitinib or with platinum-based chemotherapy with cetuximab (CT-cet) from 2010 to 2016, were considered. PD-L1 expression was assessed with immunohistochemistry on tumor cells (TCs) and on microenvironment (TC and tumor-infiltrating lymphocyte [IC] scores, respectively). Prognostic role of PD-L1 and the correlation with response to EGFR inhibitors and survival were analyzed. Results: Twenty-eight R/M sSCCs were analyzed (19 treated with dacomitinib, 9 with CT-cet). TC and IC were negative in 82 and 45% of cases, respectively; 15% sSCCs were both TC and IC positive. Progression-free survival (PFS) was longer in IC-positive cases (median 7.5 months vs. 2.1 in IC0, p = 0.02). No statistically significant differences were observed between PD-L1 expression and both overall survival and response rates. Conclusion: PD-L1 expression in microenvironment predicted better PFS. The combination of EGFR inhibitors and ICB could help deepening the knowledge about the interrelations between the EGFR and PD-1/PD-L1 pathways.

Original languageEnglish
Pages (from-to)112-118
Number of pages7
JournalOncology (Switzerland)
Issue number2
Publication statusPublished - Jul 1 2019



  • Anti-epidermal growth factor receptor treatment
  • Epidermal growth factor receptor
  • Outcome
  • PD-L1
  • Skin squamous cell carcinoma

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this