PT - JOURNAL ARTICLE AU - Ng, Cedric Chuan Young AU - Tan, Jing AU - Ong, Choon Kiat AU - Lim, Weng Khong AU - Rajasegaran, Vikneswari AU - Nasir, Nur Diyana Md AU - Lim, Jeffrey Chun Tatt AU - Thike, Aye Aye AU - Salahuddin, Syed Ahmed AU - Iqbal, Jabed AU - Busmanis, Inny AU - Chong, Angela Phek Yoon AU - Teh, Bin Tean AU - Tan, Puay Hoon TI - <em>MED12</em> is frequently mutated in breast phyllodes tumours: a study of 112 cases AID - 10.1136/jclinpath-2015-202896 DP - 2015 Sep 01 TA - Journal of Clinical Pathology PG - 685--691 VI - 68 IP - 9 4099 - http://jcp.bmj.com/content/68/9/685.short 4100 - http://jcp.bmj.com/content/68/9/685.full SO - J Clin Pathol2015 Sep 01; 68 AB - Aim To determine the frequency of MED12 mutations in a series of 112 breast phyllodes tumours, and to correlate the findings with clinicopathological parameters and survival outcomes.Methods Phyllodes tumours from the Department of Pathology, Singapore General Hospital, were classified into benign, borderline and malignant categories. Genomic DNA from formalin-fixed paraffin-embedded phyllodes tumours was extracted, purified and subjected to ultra-deep-targeted amplicon sequencing across exon 2 of the MED12 gene. Sequencing was performed on the Illumina MiSeq next-generation sequencing platform and bioinformatics analysis applied. Appropriate statistical analyses were carried out.Results There were 66 benign, 32 borderline and 14 malignant tumours, with 43 (65.1%), 21 (65.6%) and 6 (42.8%) disclosing MED12 mutations (missense, splice site, indel), respectively. For 97 cases with available follow-up, there were 10 (10.3%) recurrences. Patients with phyllodes tumours that harboured MED12 mutations experienced improved disease-free survivals, with higher recurrence likelihood in those without MED12 mutations (HR 9.99, 95% CIs 1.55 to 64.42, p=0.015).Conclusions Similar to fibroadenomas, phyllodes tumours show a high frequency of MED12 mutations, affirming the close biological relationship between these fibroepithelial neoplasms.