MMP9 and lip and oral cavity carcinoma: Finally, it was revealed that MMP-9 rs3918242 under the allelic and recessive models was remarkably related to oral cancer incidence among the overall populations (allelic model, OR = 1.309, 95% CI = 1.078–1.589, p = 0.007; recessive model, OR = 3.497, 95% CI = 1.812–6.749, p < 0.001).