Ms4a2, encoding the β chain of the high-affinity IgE receptor (FcεRIβ), is a key gene in the allergic cascade. It is involved in IgE-dependent activation of mast cells, which play important roles in allergic responses and immunity [2,3]. GATA2 and PU.1 cooperate to activate Ms4a2 gene expression through distinct mechanisms [2].

In human mast cells, a novel splice variant of Ms4a2, MS4A2(trunc), lacking exon 3 was identified. Its expression was negatively regulated by stem cell factor (SCF). Overexpression of MS4A2(trunc) induced human lung mast cell death and inhibited HMC-1 cell proliferation, indicating that Ms4a2 has multiple roles beyond regulating acute allergic responses [3]. In a mouse model of atopic dermatitis, topical emollient treatment downregulated the expression of Ms4a2 in the lung, reducing basophil activation [4]. Also, in colorectal cancer, Ms4a2 is one of the five mast cell signature genes. Mast cells in CRC show distinct activation features, and the mast cell signature is linked to a better prognosis [1].

In conclusion, Ms4a2 is crucial for mast cell-mediated immune responses and allergic reactions. Studies in models, such as the discovery of the MS4A2(trunc) splice variant in human mast cells and gene expression changes in mouse models of atopic dermatitis, have provided insights into its functions. In diseases like colorectal cancer, the role of Ms4a2 as part of the mast cell signature in prognosis further emphasizes its significance in disease-related research.