PTTG1 and breast cancer: ,51 Both PTTG1 and PTTG1IP are upregulated in several types of cancer,52,53 and it has been reported that PTTG1IP exhibits an independent transforming ability by inducing p53 degradation.54 Conversely, PTTG1IP downregulation has been reported in lung cancer tissues55 and has been associated with a higher risk of breast cancer death.56 In addition, PTTG1IP overexpression was shown to inhibit proliferation in lung cancer cells.55