The authors demonstrated that gingipain is a key virulence determinant that facilitates the entry of Porphyromonas gingivalis into CRC cells and promotes their proliferation through the activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2 (MAPK/ERK) signaling pathway [26]. The gene discussed is MAPK3; the disease is colorectal carcinoma.