MED12 and fibroepithelial neoplasm: Recently, two mechanisms are suggested to underlie the progression of the histologic grade of PT: fibroepithelial tumor and benign PT show frequent somatic MED12 mutation and additional genetic alterations are found with increasing histologic grade, whereas borderline/malignant PTs without MED12 mutation frequently harbor TP53 and PIK3CA mutations [9, 10].