Although thought to be absent or extremely rare in common forms of breast cancer18–20, TERT promoter mutations and TERT gene amplifications have been reported in up to 68% of malignant phyllodes tumors of the breast, a potential differential diagnosis of MBCs, and may have a role in the malignant progression in fibroepithelial lesions15,21,22. Here, TERT is linked to maternal uniparental disomy of chromosome 20.