IFI27 and breast cancer: Importantly, the enrichment of antigen processing pathways (e.g., the HLA family) and endoplasmic reticulum stress-related signals underscores the critical roles of immune mechanisms and protein-folding quality control in skin aging—a pattern consistent with the heightened immune-related gene expression observed in IFI27+ and BC-AS2 subpopulations, suggesting an intrinsic coupling between genetic factors and immune–inflammatory networks.