Pulmonary colonization of Candida albicans drives breast cancer lung metastasis via candidalysin

Abstract

The intratumoral mycobiome is emerging as a key modulator of cancer progression, with specific fungal taxa as potential biomarkers. However, whether and how mycobiomes colonizing distant organs contribute to tumor evolution remains largely unexplored. Here, we identify selective enrichment of Candida albicans in breast cancer lung metastases. Mechanistically, the fungal virulence factor candidalysin activates pulmonary mast cells, which release chemotactic mediators that expand immunosuppressive populations and suppress cytotoxic lymphocyte activity, remodeling the lung into a metastasis-permissive microenvironment. Analysis of clinical isolates and isogenic mutants further demonstrates that candidalysin secretion levels dictate metastasis-promoting potential. Informed by these findings, we developed a combination regimen that concurrently eliminates fungal colonization, stabilizes mast cells, and reverses the immunosuppressive microenvironment, thereby significantly curtailing metastatic progression. Collectively, our study establishes pulmonary C. albicans colonization as a driver of breast cancer lung metastasis and provides a mechanistic framework for targeting mycobiome-host interactions in metastatic disease.