Abstract 3512
Background
Both ER + HER2+ breast cancer presents a heterogeneous biology, which is yet to be explored. Thus, using the cohort of our previous phase II study, we investigated their somatic mutation profile to find out the frequency and clinical implication.
Methods
Formalin-fixed paraffin-embedded (FFPE) tissue from 21 postmenopausal ER + HER2+ breast cancer patients were obtained from Asan Medical Center. The samples were sequenced by targeted capture sequencing with NGDx (coding sequence of 585 cancer-related genes + selected introns from 57 genes). Sequenced data were mapped to the reference human genome (hg19) using the Burrows-Wheeler Aligner, and were processed using publicly available Picard and the Genome Analysis Toolkit. Single nucleotide variant calls from MuTect were filtered against the dbSNP database to enrich for somatic mutations. Copy number alterations were detected by G + C normalization of read depth of coverage.
Results
| Gene mutation | ER + HER2+ breast cancer in TCGA | Neo ALL- IN |
|---|---|---|
| PIK3CA | 38.1% | 66.7% |
| AA change/frequency | AA change/frequency | |
| Exon 9 (helical domain) | E542K: 11% E545K: 16% Q546K: 1% Q546P: ConclusionsActivating mutations in PIK3CA were abundantly found in postmenopausal ER + HER2+ breast cancer in our cohort. We carefully speculate that they might confer resistance to anti-HER-2 treatment combined with hormone therapy in neoadjuvant setting, and benefit of adding PI3K inhibitor should be considered in this subtype. Clinical trial identificationNCT 01275859 Legal entity responsible for the studyN/A FundingN/A DisclosureAll authors have declared no conflicts of interest. Resources from the same session2354 - The clinicopathologic features and treatment of 607 hindgut neuroendocrine tumor (NET) patients at a single institutionPresenter: Seung Tae Kim Session: Poster Display Resources: Abstract 2594 - Neuroendocrine carcinomas of the colorectal origin - Polish experiencePresenter: Agnieszka Kolasińska-Ćwikła Session: Poster Display Resources: Abstract 2539 - Neuroendocrine neoplasms of the appendix including goblet cell carcinoidsPresenter: Agnieszka Kolasinska-Cwikla Session: Poster Display Resources: Abstract 1245 - Prognostic validity of AJCC staging system in neuroendocrine tumors of the appendixPresenter: Amir Mehrvarz Sarshekeh Session: Poster Display Resources: Abstract 3902 - Enhancer of zest homolog 2 (EZH2) expression in well and moderately differentiated pancreatic neuroendocrine tumor (pNET)Presenter: Riccardo Marconcini Session: Poster Display Resources: Abstract 3882 - Differential clinical and pathological characteristics of hereditary neuroendocrine pancreatic tumours (NEPT)Presenter: Gema Marín Zafra Session: Poster Display Resources: Abstract 2296 - Natural course of thyroid cancer nodules compared with benign thyroid nodulesPresenter: Kyung-Jin Yun Session: Poster Display Resources: Abstract 4083 - Reassessment of proliferative activity at disease progression in neuroendocrine neoplasmsPresenter: Noemi Cicchese Session: Poster Display Resources: Abstract 3866 - 18F-FDG-PET to predict disease progression in advanced digestive neuroendocrine neoplasmsPresenter: Maria Rinzivillo Session: Poster Display Resources: Abstract 3651 - UK phase IV, observational study to assess quality of life in patients (pts) with pancreatic neuroendocrine tumours (pNETS) receiving treatment with everolimus: The “real-world” OBLIQUE studyPresenter: John Ramage Session: Poster Display Resources: Abstract This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used. For more detailed information on the cookies we use, please check our Privacy Policy.
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