Emerging roles of the host defense peptide LL‐37 in human cancer and its potential therapeutic applications

Abstract

Human cathelicidin LL‐37, a host defense peptide derived from leukocytes and epithelial cells, plays a crucial role in innate and adaptive immunity. Not only does LL‐37 eliminate pathogenic microbes directly but also modulates host immune responses. Emerging evidence from tumor biology studies indicates that LL‐37 plays a prominent and complex role in carcinogenesis. Although overexpression of LL‐37 has been implicated in the development or progression of many human malignancies, including breast, ovarian and lung cancers, LL‐37 suppresses tumorigenesis in gastric cancer. These data are beginning to unveil the intricate and contradictory functions of LL‐37. The reasons for the tissue‐specific function of LL‐37 in carcinogenesis remain to be elucidated. Here, we review the relationship between LL‐37, its fragments and cancer progression as well as discuss the potential therapeutic implications of targeting this peptide.