Androgen receptor is frequently expressed in HER2-positive, ER/PR-negative breast cancers

Virchows Arch. 2010 Oct;457(4):467-76. doi: 10.1007/s00428-010-0964-y. Epub 2010 Aug 31.

Abstract

The estrogen receptor (ER)/progesterone receptor (PR)-negative breast carcinomas (BCs) encompass three molecular subtypes: one with human epidermal growth factor receptor 2 (HER) overexpression, one normal like, and the triple negative. The androgen receptor (AR) is expressed in 70-90% of invasive BCs. The aim of our study is to detect the expression of AR in a series of ER/PR-negative BCs to ascertain if there is clinical significance in relation to BC molecular subtypes. A immunohistochemical study for all receptors and cytokeratin expression was performed in 232 cases of ER/PR-negative BCs. According to cytokeratin expression, BCs were classified into two groups: luminal-type BCs (44.2%) and basal-like-type BCs (55.8%). According to the expression of HER2, 59.3% were triple-negative BCs (when ER, PR, and HER2 were negative) and 40.7% were HER2-positive BCs. AR expression was observed in 128 tumors (56.6%). One hundred and ten cases (48.8%) had >10% and 18 (7.8%) had <10% of positively stained cells. AR immunoreactivity was found in 31.2% basal-like BCs, while in the luminal group 71.1% of cases were positive, showing highly significant correlation (p < 10⁻⁸). Regarding HER2 status, 76.7% of HER2-positive BC cases were AR positive compared with only 30.4% of triple-negative BC types, showing a strong statistically significant correlation. In conclusion, we show that AR is frequently expressed in ER/PR-negative BCs and that expression of HER2 and AR is highly correlated (p < 0.005). Our results point out the role of AR and HER2 in the pathogenesis of BCs and suggest the potential role of AR in clinical management of ER/PR-negative BCs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Breast Neoplasms / chemistry*
  • Breast Neoplasms / mortality
  • Breast Neoplasms / pathology
  • Female
  • Humans
  • Immunohistochemistry
  • Middle Aged
  • Receptor, ErbB-2 / analysis*
  • Receptors, Androgen / analysis*
  • Receptors, Estrogen / analysis*
  • Receptors, Progesterone / analysis*

Substances

  • Receptors, Androgen
  • Receptors, Estrogen
  • Receptors, Progesterone
  • ERBB2 protein, human
  • Receptor, ErbB-2