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Immunohistochemical Staining of B7-H1 (PD-L1) on Paraffin-embedded Slides of Pancreatic Adenocarcinoma Tissue
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Costimulatory molecule B7-H1 in primary and metastatic clear cell renal cell carcinoma

R Houston Thompson1, Michael D Gillett, John C Cheville

  • 1Department of Urology, Mayo Medical School, Mayo Clinic, Rochester, Minnesota 55905, USA.

Cancer
|October 7, 2005
PubMed
Abstract

Insights

High B7-H1 expression in renal cell carcinoma (RCC) correlates with increased mortality. This study found B7-H1 is also present in RCC metastases, suggesting B7-H1 blockade could enhance immunotherapy for advanced kidney cancer.

Area of Science:

  • Immunology
  • Oncology
  • Medical Research

Background:

  • B7-H1 (programmed death-ligand 1) is a molecule expressed by cancer cells that inhibits anti-tumor immune responses.
  • Previous studies indicated aberrant B7-H1 expression in primary renal cell carcinoma (RCC).
  • B7-H1 blockade is a potential therapeutic strategy for RCC, but its role in metastatic disease was unknown.

Purpose of the Study:

  • To update findings on B7-H1 expression in primary RCC.
  • To investigate B7-H1 expression in metastatic RCC.
  • To assess the prognostic significance of B7-H1 in RCC.

Main Methods:

  • Immunohistochemical analysis of B7-H1 expression on tumor cells and lymphocytes in 196 primary RCC and 26 metastatic RCC specimens.
  • Quantification of B7-H1-positive cells by a urologic pathologist.
  • Statistical analysis including risk ratio and multivariate analysis.

Main Results:

  • High B7-H1 expression was observed in 66.3% of primary RCC tumor cells and 58.7% of tumor-infiltrating lymphocytes.
  • Patients with high B7-H1 expression had a significantly higher risk of death from RCC (RR=4.17).
  • B7-H1 was expressed in 65.4% of metastatic RCC cells and 69.2% of lymphocytes, with 54.3% showing high aggregate levels.

Conclusions:

  • High B7-H1 expression is a significant negative prognostic factor in RCC, even after multivariate analysis.
  • RCC metastases frequently express B7-H1, similar to primary tumors.
  • Targeting B7-H1 may enhance immunotherapy for RCC, including patients with metastatic disease.

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