Immunohistochemical assessment of HRAS Q61R mutations in breast adenomyoepitheliomas

• DOI: 10.1111/his.14057
• Publication Date: 2019-12-30T17:44:39Z
• Authors: Fresia Pareja; Michael S Toss; Felipe C Geyer; Edaise M da Silva; Mahsa Vahdatinia; Ana Paula M Sebas...; Pier Selenica; Austin Szatrowski; Marcia Edelweiss; Hannah Y Wen; Raluca Mihai; Zsuzsanna Varga; Maria P Foschini; Brian P Rubin; Ian O Ellis; Sarat Chandarlapaty; Achim A Jungbluth; Edi Brogi; Britta Weigelt; Jorge S Reis‐Filho; Emad A Rakha
• Keywords: HRAS

Aims Breast adenomyoepitheliomas (AMEs) are uncommon tumours. Most oestrogen receptor (ER)‐positive AMEs have mutations in phosphoinositide 3‐kinase (PI3K) pathway genes, whereas ER‐negative usually harbour concurrent affecting the HRAS Q61 hotspot and PI3K genes. Here, we sought to determine sensitivity specificity of RAS Q61R immunohistochemical (IHC) analysis for detection AMEs. Methods results Twenty‐six (14 ER‐positive; 12 ER‐negative) previously subjected massively parallel sequencing ( n = 21) or Sanger 5) locus were included this study. All IHC with a monoclonal (SP174) Q61R‐specific antibody, addition detailed histopathological analysis. Nine harboured mutations, including 7) Q61K 2) mutations. Five seven (71%) immunohistochemically positive, none lacking 17) immunoreactive. immunoreactivity was restricted myoepithelium 80% (4/5) cases, one case showed both epithelial component myoepithelial component. positive associated infiltrative borders P < 0.001), necrosis 0.01) mitotic index 0.05) components. assessment did not reveal (0/2). Conclusions shows high (100%) moderate breast AMEs, appears detect may constitute useful technique diagnostic workup