Pathology and Laboratory Medicine
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Visual summary · Pathology and Laboratory Medicine

The Prognostic Value of PD-L1 Expression in Triple-Negative Breast Cancer: A Cohort Study and Systematic Literature Review

Daniel Schmolze, Carolyn E. Behrendt, Peter P. Lee, Sophia Apple

The question

In primary triple-negative breast cancer (TNBC), is tumor expression of PD-L1 prognostic of survival?

  • If so, is PD-L1 expression in stromal and immune cells as prognostic as PD-L1 in tumor cells?
  • The prognostic value of programmed death ligand-1 (PD-L1) in triple-negative breast cancer (TNBC) is unclear.

What was done

112patients studied
308cores of TNBC contributed
22similar studies reviewed
  • Surgical specimens of primary TNBC were linked to data on recurrence-free survival (RFS).
  • Tissue microarray averaging 3 tumor cores per case underwent immunohistochemical staining.
  • Within each core, PD-L1 positivity was scored separately for tumor, stromal, and immune cells by averaging readings by two board-certified pathologists.
  • Comparable survival analyses were identified by systematic search of MEDLINE-indexed journals through March 2019.

Key findings

Finding 1 of 3
8.9%
subjects with High PD-L1 expression on tumor cells

Ten (8.9%) subjects had High PD-L1 expression on tumor cells, a feature associated with better RFS.

Finding 2 of 3
0.44
hazards ratio for better recurrence-free survival

High PD-L1 on tumor cells was associated with better recurrence-free survival with a hazards ratio of 0.44.

Finding 3 of 3
16
of 22 similar studies found survival associations

Among 22 similar studies, high PD-L1 on tumor cells was associated with survival in 16 studies: 7 favorably, 8 unfavorably, and 1 with mixed results.

Why it matters

  • In this TNBC cohort, High PD-L1 on tumor cells conferred favorable prognosis.
  • The lack of consensus across similar studies suggests that future studies should explore how timing, microenvironment, and glycosylation influence PD-L1’s association with survival.

How to cite

Daniel Schmolze, Carolyn E. Behrendt, Peter P. Lee, Sophia Apple. The Prognostic Value of PD-L1 Expression in Triple-Negative Breast Cancer: A Cohort Study and Systematic Literature Review. Pathology and Laboratory Medicine. 2019;2(1):1-8. https://doi.org/10.17140/plmoj-2-107

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