MMP7 and cancer: Therefore, here we hypothesized that overexpressed S100A8/A9 as the secreted soluble inflammatory factors in tumor microenvironment might enhance the activity/phosphorylation of the p38 MAPK pathway in cancer cells, which subsequently activated the transcriptional factors and elevated the tumor cell invasion and migration protein expression (e.g., MMP7) and finally promoted NPC cell proliferation, migration, and invasion (Figure 5).