In lung cancer cells for example, proliferation is regulated through the Kras–Erk–NF-kB–Timp1–CD63–FAK–Erk loop: activation of the cellular proliferation process through this pathway requires Timp1 and its receptor CD63, and Timp1 is the target gene for NF-kB (59). The gene discussed is NFKB1; the disease is lung carcinoma.