MED12 and Fibroadenoma: The mutations of this gene involved in the transcriptional regulation of gene expression have been observed in 65%-85% of benign and borderline phyllodes tumors and decrease in B-MPT (20-40% of cases), indicating their occurrence as an early event in the evolution of phyllodes tumors.6,7,11,12 Consistently, Pareja et al7 showed that MED12 mutations were significantly more frequent in phyllodes tumors with fibroadenoma-like areas (71% vs 11%; P < .05), while EGFR alterations were significantly less frequent (14% vs 78%; P < .05).