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Background: Patients with Estrogen Receptor α-positive (ER+) Inflammatory Breast Cancer (IBC) are less responsive to endocrine therapy compared with ER+ non-IBC (nIBC) patients. The study of ER+ IBC samples might reveal biomarkers for endocrine resistant breast cancer., Materials & Methods: Gene expression profiles of ER+ samples from 201 patients were explored for genes that discriminated between IBC and nIBC. Classifier genes were applied onto clinically annotated expression data from 947 patients with ER+ breast cancer and validated with RT-qPCR for 231 patients treated with first-line tamoxifen. Relationships with metastasis-free survival (MFS) and progression-free survival (PFS) following adjuvant and first-line endocrine treatment, respectively, were investigated using Cox regression analysis., Results: A metagene of six genes including the genes encoding for 4-aminobutyrate aminotransferase (ABAT) and Stanniocalcin-2 (STC2) were identified to distinguish 22 ER+ IBC from 43 ER+ nIBC patients and remained discriminatory in an independent series of 136 patients. The metagene and two genes were not prognostic in 517 (neo)adjuvant untreated lymph node-negative ER+ nIBC breast cancer patients. Only ABAT was related to outcome in 250 patients treated with adjuvant tamoxifen. Three independent series of in total 411 patients with advanced disease showed increased metagene scores and decreased expression of ABAT and STC2 to be correlated with poor first-line endocrine therapy outcome. The biomarkers remained predictive for first-line tamoxifen treatment outcome in multivariate analysis including traditional factors or published signatures. In an exploratory analysis, ABAT and STC2 protein expression levels had no relation with PFS after first-line tamoxifen., Conclusions: This study utilized ER+ IBC to identify a metagene including ABAT and STC2 as predictive biomarkers for endocrine therapy resistance., (Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)

The histological characteristics of phyllodes tumours of the breast are often not related to their clinical outcome. Additional studies must therefore be performed to investigate the possible relationship of cell biological parameters to the biological behaviour of these tumours. The expression of Ki-67, p53, and its regulated proteins has been studied in 19 primary phyllodes tumours, from patients with known follow-up, using immunohistochemical and molecular biological techniques. Overexpression of the p53 protein was observed in four cases and mutation in two cases. In only one case, the sequence alteration, at codon 273, was associated with overexpression of p53 protein and with strong expression of Ki-67 (30 per cent). This alteration was found in the primary, the recurrent, and the metastatic tumour samples. Moreover, the same p53 gene mutation, Arg273Cys, was detected in all tumour samples. No mutation was found in adjacent normal breast tissue, indicating that this was an acquired mutation. Unexpectedly, strong BAX expression was observed in the primary tumour. The patient died during the follow-up period. It is concluded that p53 gene status and an accumulation of BAX, both involved in the same apoptosis-controlling pathway, may be of prognostic relevance in phyllodes tumours., (Copyright 1999 John Wiley & Sons, Ltd.)