Surface expression of TGFβ docking receptor GARP promotes oncogenesis and immune tolerance in breast cancer

Alessandra Metelli, Bill X. Wu, Caroline W. Fugle, Saleh Rachidi, Shaoli Sun, Yongliang Zhang, Jennifer Wu, Stephen Tomlinson, Philip H. Howe, Yi Yang, Elizabeth Garrett-Mayer, Bei Liu, Zihai Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


GARP encoded by the Lrrc32 gene is the cell surface docking receptor for latent TGFβ, which is expressed naturally by platelets and regulatory T cells (Treg). Although Lrrc32 is amplified frequently in breast cancer, the expression and relevant functions of GARP in cancer have not been explored. Here, we report that GARP exerts oncogenic effects, promoting immune tolerance by enriching and activating latent TGFβ in the tumor microenvironment. We found that human breast, lung, and colon cancers expressed GARP aberrantly. In genetic studies in normal mammary gland epithelial and carcinoma cells, GARP expression increased TGFβ bioactivity and promoted malignant transformation in immunodeficient mice. In breast carcinoma-bearing mice that were immunocompetent, GARP overexpression promoted Foxp3+ Treg activity, which in turn contributed to enhancing cancer progression and metastasis. Notably, administration of a GARP-specific mAb limited metastasis in an orthotopic model of human breast cancer. Overall, these results define the oncogenic effects of the GARP-TGFβ axis in the tumor microenvironment and suggest mechanisms that might be exploited for diagnostic and therapeutic purposes.

Original languageEnglish (US)
Pages (from-to)7106-7117
Number of pages12
JournalCancer Research
Issue number24
StatePublished - Dec 15 2016

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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