The involvement of PTTG1 in tumor growth and metastasis is further highlighted by several studies showing that in cancer cell lines of various histological derivation ectopic expression of PTTG1 enhanced proliferation and/or invasiveness, whereas PTTG1 silencing produced opposite results [7, 8, 10–12, 17–22]. The gene discussed is PTTG1; the disease is neoplasm.