title: EZH2 expression correlates with locoregional recurrence after radiation in inflammatory breast cancer.
abstract: BACKGROUND
  Enhancer of zeste homolog 2 (EZH2), a member of the polycomb group proteins, has been shown to promote cancer progression and breast cancer stem cell (CSC) expansion. Breast CSCs are associated with resistance to radiation in inflammatory breast cancer (IBC), a rare but aggressive variant of breast cancer. In this retrospective study, we examined the clinical role of EZH2 in locoregional recurrence (LRR) of IBC patients treated with radiation.
  
  
  METHODS
  62 IBC patients who received radiation (7 pre-operative, 55 post-operative) and had adequate follow up to assess LRR were the subject of this study. Positive EZH2 status was defined as nuclear immunohistochemical staining in at least 10% of invasive cancer cells. Association of EZH2 expression with clinicopathologic features were evaluated using the Chi-square statistic and actuarial LRR free survival (LRFS) was determined using the Kaplan-Meier method.
  
  
  RESULTS
  The median follow-up for this cohort was 33.7 months, and the 5-year overall LRFS rate was 69%. Of the 62 patients, 16 (25.8%) had LRR, and 15 out of 16 LRR occurred in EZH2 expressing cases. Univariate analysis indicated that patients who had EZH2-positive IBC had a significantly lower 5-year locoregional free survival (LRFS) rate than patients who had EZH2-negative IBC (93.3% vs. 59.1%; P = 0.01). Positive EZH2 expression was associated significantly with negative ER status (97.1% in ER- vs 48.1% in ER+; P < 0.0001) and triple-negative receptor status (P = 0.0001) and all triple-negative tumors were EZH2-positive. In multivariate analysis, only triple negative status remained an independent predictor of worse LRFS (hazard ratio 5.64, 95% CI 2.19 - 14.49, P < 0.0001).
  
  
  CONCLUSIONS
  EZH2 correlates with locoregional recurrence in IBC patients who received radiation treatment. EZH2 expression status may be used in addition to receptor status to identify a subset of patients with IBC who recur locally in spite of radiation and may benefit from enrollment in clinical trials testing radiosensitizers.
authors: Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. bgdebeb@mdanderson.org.|Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA. bgdebeb@mdanderson.org.
authors: Bisrat G
authors: BG
authors: Debeb
authors: Department of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. yungong@mdanderson.org.|Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA. yungong@mdanderson.org.
authors: Yun
authors: Y
authors: Gong
authors: Department of Clinical Cancer Prevention, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. ratkinson@mdanderson.org.|Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA. ratkinson@mdanderson.org.
authors: Rachel L
authors: RL
authors: Atkinson
authors: Department of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. nsneige@mdanderson.org.
authors: Nour
authors: N
authors: Sneige
authors: Department of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. leihuo@mdanderson.org.|Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA. leihuo@mdanderson.org.
authors: Lei
authors: L
authors: Huo
authors: Department of Breast Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. agonzalez@mdanderson.org.
authors: Ana Maria
authors: AM
authors: Gonzalez-Angulo
authors: Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. mhung@mdanderson.org.|Center for Molecular Medicine and Graduate Institute of Cancer Biology, China Medical University, Taichung, Taiwan. mhung@mdanderson.org.
authors: Mien-Chie
authors: MC
authors: Hung
authors: Department of Breast Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. vvalero@mdanderson.org.|Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA. vvalero@mdanderson.org.
authors: Vicente
authors: V
authors: Valero
authors: Department of Breast Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. nueno@mdanderson.org.|Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA. nueno@mdanderson.org.
authors: Naoto T
authors: NT
authors: Ueno
authors: Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA. wwoodward@mdanderson.org.|Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA. wwoodward@mdanderson.org.|Division of Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Unit 1202, 77030, Houston, TX, USA. wwoodward@mdanderson.org.
authors: Wendy A
authors: WA
authors: Woodward
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis*; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D000071221:Enhancer of Zeste Homolog 2 Protein; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D058922:Inflammatory Breast Neoplasms / Q000737:chemistry* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local; D063151:Polycomb Repressive Complex 2 / Q000032:analysis*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D064726:Triple Negative Breast Neoplasms / Q000737:chemistry* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*
chemical_list: D014408:Biomarkers, Tumor; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2