Huijuan Wang

Background/Objectives: Breast cancer is the leading cause of cancer-related mortality in women, highlighting the urgent need for robust prognostic tools to enable individualized risk stratification. Methods: Transcriptomic data from 1075 breast cancer and 113 adjacent normal tissues in The Cancer Genome Atlas (TCGA) were integrated with clinical information. Differential expression analysis identified 531 immune-related genes, which were further selected by univariate Cox regression and Least Absolute Shrinkage and Selection Operator (LASSO) regression to construct a 13-gene prognostic signature. The model was validated in an independent cohort (n = 327). Tumor immune microenvironment and single-cell RNA sequencing data were analyzed to explore underlying biological differences. Results: The 13-gene signature effectively stratified patients into low- and high-risk groups with significantly different overall survival in both the TCGA cohort (log-rank p < 0.0001; C-index = 0.678; 5-year AUC = 0.72) and the validation cohort (log-rank p < 0.0001; C-index = 0.703; 3-year AUC = 0.81). Low-risk tumors exhibited an antitumor immune microenvironment enriched in CD8⁺ T cells, T follicular helper (Tfh) cells, and M1 macrophages, whereas high-risk tumors were dominated by immunosuppressive regulatory T cells and M2 macrophages (all p < 0.0001). Single-cell analysis revealed expansion of malignant epithelial cells and inflammatory cancer-associated fibroblasts (iCAFs) in high-risk tumors, with higher iCAF scores significantly associated with poorer survival (log-rank p = 0.00036). Conclusions: Collectively, this study delivers a rigorously validated 13-gene immune signature whose prognostic utility is rooted in distinct immune microenvironmental features, while unveiling iCAF-targeted therapeutic strategies as a promising intervention avenue.

Although biologics have been revolutionizing the treatment of inflammatory bowel diseases (IBD) over the past decade, a significant number of patients still fail to benefit from these drugs. Overcoming the nonresponse to biologics is one of the top challenges in IBD treatment. In this study, we revealed that hyaluronan (HA), an extracellular matrix (ECM) component in the gut, is associated with nonresponsiveness to infliximab and vedolizumab therapy in patients with IBD. In murine colitis models, inhibition of HA synthase 2–mediated (HAS2-mediated) HA synthesis sensitized the therapeutic response to infliximab. Mechanistically, HA induced the expression of MMP3 in colonic fibroblasts by activating STAT3 signaling, thereby mediating the proteolytic cleavage of multiple IgG1 biologics. Finally, we found that macrophage-derived factors upregulated HAS2 expression in fibroblasts, thereby contributing to infliximab nonresponse. In summary, we identified a pathogenic connection between abnormal ECM remodeling and biologics nonresponse and provided insights for the precise therapy for IBD.