Phyllodes tumors of the breast, as a group, displayed a significantly higher frequency of mutations affecting MED12 (59% vs 5%, Fisher's exact test, P = 0.0002) and the promoter of TERT (45% vs 0, Fisher's exact test, P = 0.0006, Fig. 3, Table S2) than adenosarcomas. This evidence concerns the gene MED12 and breast phyllodes tumor.