title: EZH2 expression in invasive lobular carcinoma of the breast.
abstract: BACKGROUND
  Invasive lobular carcinoma (ILC) is the second most common histologic type of breast cancer, but the prognosis of ILC is still controversial. Enhancer of Zeste homolog 2 (EZH2), the catalytic subunit of the Polycomb repressive complex 2 (PRC2), is frequently overexpressed in various cancers. This study evaluated the relationship between clinicopathologic characteristics and EZH2 expression.
  
  
  METHODS
  We retrospectively reviewed the medical records of 54 patients with ILC and selected 49 cases of ILC. Immunohistochemistry for EZH2 was undertaken.
  
  
  RESULTS
  We defined ILC as discohesive cells with a linear or nonlinear growth pattern. No statistically significant difference was found for most variables, including multifocality, menstrual status, body mass index, tumor stage (pT), lymph node stage (pN), estrogen receptor, and progesterone receptor. In contrast, nuclear grade was statistically significant and EZH2 expression was associated with high nuclear grade. In total, 80% of nuclear grade 3 cases had an EZH2 score of 4, and 86% of nuclear grade 1 cases had EZH2 scores of 1 and 2. Our cases had a score of 3 for tubule formation and a score of 1 for mitosis, and so the histologic grading consisted of grades 1 (7 cases) and 2 (42 cases) depending on the nuclear grade.
  
  
  CONCLUSIONS
  Although EZH2 could not predict survival in our study, EZH2 expression was associated with a high nuclear grade. Most ILCs have histologic grade 2 with nuclear grade 2 or 3. Therefore, our opinion is that if ILC is diagnosed by separating the classic type and variants and considering both EZH2 expression and nuclear grade, EZH2 overexpression could help and the Nottingham grading system would be more accurate prognostic factor.
authors.affiliation: Department of Pathology, Konyang University College of Medicine and Konyang University Myunggok Medical Research Institute, 158 Gwanjeodong-ro, Seo-Gu, Daejeon 302-718, South Korea. car754@naver.com.
authors.forename: SiGyun
authors.initials: S
authors.lastname: Roh
authors.forename: Shin Young
authors.initials: SY
authors.lastname: Park
authors.forename: Hyoung Suk
authors.initials: HS
authors.lastname: Ko
authors.forename: Jang Sihn
authors.initials: JS
authors.lastname: Sohn
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Cha
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018275:Carcinoma, Lobular / Q000378:metabolism* / Q000473:pathology; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology*; D000071221:Enhancer of Zeste Homolog 2 Protein; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D063151:Polycomb Repressive Complex 2 / Q000378:metabolism*; D011379:Prognosis; D012189:Retrospective Studies
chemical_list: D014408:Biomarkers, Tumor; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2