Plenary lecture: Molecular genomics of breast fibroepithelial tumours – Bin Tean Teh, National Cancer Centre, Singapore

16:45-17:25

Room: Hall 1A

Breast fibroepithelial tumors constitute a distinct category in breast disease. Distinct from breast carcinoma, they comprise a heterogeneous spectrum of pathological entities, from benign fibroadenomas to malignant phyllodes tumors. We have recently profiled the genomic landscape of this group of tumors (Lim et al., Nat Genet, 2014; Tan et al., Nat Genet, 2015).. First, MED12 and RARA mutations are frequently found in both fibroadenomas and phyllodes tumors, emphasizing the importance of these mutations in fibroepithelial tumorigenesis. Second, phyllodes tumors exhibited mutations in FLNA, SETD2 and KMT2D, suggesting a role in driving phyllodes tumor development. Third, borderline and malignant phyllodes tumors harbored additional mutations in common cancer-associated genes such as p53, RB1, etc. RARA mutations exhibited clustering in the portion of the gene encoding the ligand-binding domain, functionally suppressed RARA-mediated transcriptional activation and enhanced RARA interactions with transcriptional co-repressors. The clinical implications of these findings will be discussed.