PTTG1 and breast cancer: Moreover, we also analyzed the correlation between PTTG1 expression and some clinical parameters, such as gender, age, tumor size, histologic grade, TNM stage, lymphatic invasion and distant metastasis, and found increased PTTG1 expression was correlated with tumor size, TNM stage, lymphatic invasion and distant metastasis, but there was no significant correlation between PTTG1 with other clinical pathologic characteristics including gender, age, or histologic grade in BC (Table 1).