In GC, the epithelial protein loss frequency was 60.67% (108/178) for E-cadherin (Table 1 and Figure 1C, 1F), and aberrant metastasis protein expression frequencies were 74.15% (132/178) for MMP2 (Table 1 and Figure 1D), which was detected primarily in the cytoplasm. Here, MMP2 is linked to gastric cancer.