KLK1 and cancer: To explore the expression of KLK1 and B1R in the colitis‐cancer transformation model, we constructed an AOM‐DSS‐induced colitis‐cancer transformation model in mice, obtained intestinal tissues for single‐cell sequencing (Figure7A), identified cell subpopulations and performed dimensionality reduction clustering analysis, and divided the cells into five subpopulations: epithelial cells, stromal cells, T cells, B cells, and myeloid cells and found that Klk1 was highly expressed specifically in goblet cells (Figure 7B,C).