TACSTD2 and neoplasm: Therefore, the five cell types with increased or decreased abundance in the tumor group, namely, tissue stem cells, epithelial cells, endothelial cells, macrophages, and smooth muscle cells, were subjected to further analysis, and the distribution of the biomarkers TACSTD2, ENTPD1, and SERPINA1 in these five cell types was plotted (Figure 5C).