Indeed, we observed that the MMP-9 signal was localized within the cytoplasm in both the fibroblasts and the HCT-116 cells in the 3D CRC μTs, especially in the cell protrusions of the plasma membrane (Figure 5G: yellow and white arrows for HCT-116 cells and fibroblasts, respectively). The gene discussed is MMP9; the disease is colorectal carcinoma.