Candida albicans in Oral Squamous Cell Carcinoma: From Microbial Dysbiosis to Tumor-Promoting Mechanisms and Translational Opportunities.

Oral squamous cell carcinoma (OSCC) remains a major global health burden with limited improvement in survival rates. While traditional risk factors such as tobacco and alcohol are well established, increasing evidence highlights the role of the oral microbiome in carcinogenesis. Among microbial species, Candida albicans (C. albicans) has emerged as a potential contributor to tumor-promoting processes. Clinical studies consistently report increased fungal colonization in oral potentially malignant disorders and OSCC, with associations to disease severity and recurrence. Mechanistically, C. albicans contributes to carcinogenesis through acetaldehyde production, chronic inflammation, oxidative stress, epithelial signaling modulation, and extracellular vesicle (EV)-mediated communication. These pathways promote tumor microenvironment remodeling and epithelial transformation. However, conflicting evidence exists regarding causality, suggesting that fungal colonization may also result from tumor-associated ecological changes. From a translational perspective, C. albicans and EV-associated signatures may represent promising biomarkers and therapeutic targets, although further validation is required. This review highlights the emerging role of fungal-host interactions in OSCC and underscores their potential in microbiome-informed precision oncology.