Secretory Leukocyte Protease Inhibitor (SLPI) in mucosal tissues: Protects against inflammation, but promotes cancer

Sandrine Nugteren, Janneke N. Samsom*

*Corresponding author for this work

Research output: Contribution to journalReview articleAcademicpeer-review

28 Citations (Scopus)
108 Downloads (Pure)


The immune system is continuously challenged with large quantities of exogenous antigens at the barriers between the external environment and internal human tissues. Antimicrobial activity is essential at these sites, though the immune responses must be tightly regulated to prevent tissue destruction by inflammation. Secretory Leukocyte Protease Inhibitor (SLPI) is an evolutionarily conserved, pleiotropic protein expressed at mucosal surfaces, mainly by epithelial cells. SLPI inhibits proteases, exerts antimicrobial activity and inhibits nuclear factor-kappa B (NF-κB)-mediated inflammatory gene transcription. SLPI maintains homeostasis at barrier tissues by preventing tissue destruction and regulating the threshold of inflammatory immune responses, while protecting the host from infection. However, excessive expression of SLPI in cancer cells may have detrimental consequences, as recent studies demonstrate that overexpression of SLPI increases the metastatic potential of epithelial tumors. Here, we review the varied functions of SLPI in the respiratory tract, skin, gastrointestinal tract and genitourinary tract, and then discuss the mechanisms by which SLPI may contribute to cancer.

Original languageEnglish
Pages (from-to)22-35
Number of pages14
JournalCytokine and Growth Factor Reviews
Early online date12 May 2021
Publication statusPublished - Jun 2021

Bibliographical note

Funding Information:
Sandrine Nugteren was funded by the Dutch Digestive Foundation (grant registration number: Focus Project 15-17).

Publisher Copyright:
© 2021


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