COL1A1 and cancer: Reclustering the spots in the tumor region led to the identification of five subregions corresponding to five gene modules (Fig. 4d): C0 spots expressed high levels of collagen, which is the major component of the TME and participates in cancer fibrosis [61], including collagen type III (COL3A1), COL4A2, COL4A1, COL6A2, COL1A2, and COL1A1. In contrast to C1 spots, C0 spots in the outermost layer in the CRC5_1 section, constituted the primary structural element of the ECM.