A Case Series of Metastatic Metaplastic Breast Carcinoma Treated With Anti-PD-1 Therapy

Isaac Kim, Venkatesh Rajamanickam, Brady Bernard, Brie Chun, Yaping Wu, Maritza Martel, Zhaoyu Sun, William L. Redmond, Katherine Sanchez, Reva Basho, Heather McArthur, David B. Page

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Metaplastic breast cancer is a rare and often chemo-refractory subtype of breast cancer with poor prognosis and limited treatment options. Recent studies have reported overexpression of programmed death ligand 1 (PD-L1) in metaplastic breast cancers, and there are several reports of anti-PD-1/L1 being potentially active in this disease. In this case series, we present 5 patients with metastatic metaplastic breast cancer treated with anti-PD-1-based therapy at a single center, with 3 of 5 cases demonstrating a response to therapy, and one of the responding cases being a metaplastic lobular carcinoma with low-level hormone receptor expression. Cases were evaluated for PD-L1 expression, tumor infiltrating lymphocytes (TILs), DNA mutations, RNA sequencing, and T-cell receptor sequencing. Duration of the response in these cases was limited, in contrast to the more durable responses noted in other recently published reports.

Original languageEnglish (US)
Article number635237
JournalFrontiers in Oncology
StatePublished - Jun 8 2021
Externally publishedYes


  • PD-L1
  • PI3K
  • TNBC
  • immunotherapy
  • metaplastic breast cancer

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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