Frontiers in Oncology (Sep 2021)

Case Report: A Case Study Documenting the Activity of Atezolizumab in a PD-L1-Negative Triple-Negative Breast Cancer

  • Fara Brasó-Maristany,
  • Fara Brasó-Maristany,
  • Miriam Sansó,
  • Miriam Sansó,
  • Nuria Chic,
  • Nuria Chic,
  • Débora Martínez,
  • Débora Martínez,
  • Blanca González-Farré,
  • Blanca González-Farré,
  • Esther Sanfeliu,
  • Esther Sanfeliu,
  • Lucio Ghiglione,
  • Esther Carcelero,
  • Javier Garcia-Corbacho,
  • Javier Garcia-Corbacho,
  • Marcelo Sánchez,
  • Dolors Soy,
  • Pedro Jares,
  • Vicente Peg,
  • Cristina Saura,
  • Cristina Saura,
  • Cristina Saura,
  • Montserrat Muñoz,
  • Montserrat Muñoz,
  • Aleix Prat,
  • Aleix Prat,
  • Aleix Prat,
  • Aleix Prat,
  • Aleix Prat,
  • Aleix Prat,
  • Ana Vivancos

DOI
https://doi.org/10.3389/fonc.2021.710596
Journal volume & issue
Vol. 11

Abstract

Read online

The immune checkpoint inhibitor atezolizumab is approved for PD-L1-positive triple-negative breast cancer (TNBC). However, no activity of atezolizumab in PD-L1-negative TNBC has been reported to date. Here, we present the case study of a woman with TNBC with low tumor infiltrating lymphocytes and PD-L1-negative disease, which achieved a significant response to atezolizumab monotherapy and durable response after the combination of atezolizumab and nab-paclitaxel. The comprehensive genomic analysis that we performed in her tumor and plasma samples revealed high tumor mutational burden (TMB), presence of the APOBEC genetic signatures, high expression of the tumor inflammation signature, and a HER2-enriched subtype by the PAM50 assay. Some of these biomarkers have been shown to independently predict response to immunotherapy in other tumors and may explain the durable response in our patient. Our work warrants further translational studies to identify biomarkers of response to immune checkpoint inhibitors in TNBC beyond PD-L1 expression and to better select patients that will benefit from immunotherapy.

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