MS4A2 encodes the β-subunit of the high-affinity IgE receptor (FcεRI), a critical component in allergic responses and mast cell activation 1. The protein functions as part of a multi-subunit receptor complex that binds IgE with high affinity, triggering mast cell degranulation and release of inflammatory mediators when cross-linked by allergens 2. MS4A2 expression is regulated by transcription factors including GATA2, which directly transactivates the MS4A2 promoter 1. Genetic polymorphisms in MS4A2, particularly the E237G variant (rs569108), are associated with increased risk of atopic asthma and eczema development, with the GG genotype showing significant association with childhood eczema 34. The -109T/C promoter polymorphism demonstrates ethnic-specific associations with asthma risk in Asian populations and correlates with altered FcεRIβ transcript levels 5. Beyond allergic diseases, MS4A2 shows paradoxical roles in cancer, with elevated expression in lung adenocarcinoma associated with improved survival outcomes through modulation of tumor-associated mast cells and immune microenvironment 6. In chr11 rhinosinusitis, elevated MS4A2 expression correlates with poor postoperative prognosis, particularly in refractory cases with increased mast cell-IgE interactions 2.