Mucin dysregulation in salivary gland tumorigenesis: Diagnostic, prognostic, and therapeutic insights: A systematic review & meta-analysis.

BACKGROUND: Salivary gland tumors (SGTs) comprise a heterogeneous group of neoplasms with overlapping histopathological features, making diagnosis and classification challenging Mucins(MUCs) are high molecular weight glycoproteins involved in epithelial differentiation and tumorigenesis which have emerged as potential biomarkers in salivary gland pathology. METHODOLOGY: A thorough review and meta-analysis were conducted across PubMed, Scopus, Web of Science, and Embase until February 2025 to elucidate the diagnostic, prognostic, and therapeutic significance of mucin differential expression in benign and malignant SGTs. RESULT: Twenty-nine articles encompassing 1657 salivary gland cases were included. Data on mucins, their localization, and expression pattern using immunohistochemistry, RT-PCR, or ELISA were evaluated. MUC1 and MUC4 were predominantly expressed in PA and MEC, with MUC1 associated with high-grade MECs and recurrence in PA. MUC4 showed higher expression in low-grade MECs and was diagnostically specific for secretory carcinoma. MUC1 showed high expression in both MEC and PA, but the pooled odds ratios [MEC: OR = 2.23; PA: OR = 0.35] were statistically non-significant (p > 0.05), with moderate heterogeneity (I2 = 53% for MEC) and poor subgroup differences. MUC4 had a sensitivity of 81% but exhibited near-zero specificity (0%), and its odds ratio (0.85 [95% CI: 0.17-4.30]) lacked statistical significance. CONCLUSION: Mucins demonstrate differential expression across salivary gland tumors and may complement histopathological evaluation. However, the current quantitative evidence remains insufficient to support their use as standalone diagnostic biomarkers due to limited specificity and considerable uncertainty in pooled estimates.