title: Magnetic resonance imaging features of breast cancer according to intrinsic subtypes: correlations with neoadjuvant chemotherapy effects.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the magnetic resonance imaging (MRI) features of breast cancer according to intrinsic subtypes and to investigate whether the MRI and immunohistochemical findings were related to neoadjuvant chemotherapy (NAC) effects.
  
  
  METHODS
  The MRI in 116 women with breast cancers who underwent NAC was reviewed. The mass margin, presence of intratumoral necrosis, tumor extension around the mass, relative signal enhancement (RSE), and kinetic curve pattern were analyzed. We investigated the possible correlations between MRI findings and the effects of NAC.
  
  
  RESULTS
  An irregular mass margin was significantly associated with luminal-A cancers, while a smooth mass margin was associated with human epidermal growth factor receptor2 (HER2) cancers. Intratumoral necrosis was significantly associated with triple-negative cancers. Tumor extension around the mass was significantly infrequent in luminal-B cancers and frequent in HER2 cancers. Luminal-B and HER2 cancers showed a significantly higher RSE at 2 min than Luminal-A cancers. Estrogen receptor (ER)-positive cancers, HER2-negative cancers, and presence of intratumoral necrosis were significantly associated with the NAC non-response.
  
  
  CONCLUSIONS
  Several MR features can be used to predict the intrinsic subtype of breast cancers. ER-positivity, HER2-negativity, and presence of intratumoral necrosis were significantly associated with NAC non-response.
authors.affiliation: Department of Quantum Medical Technology, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942 Japan ; Section of Breast Oncology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641 Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kawashima
authors.affiliation: Section of Breast Oncology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641 Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Inokuchi
authors.affiliation: Section of Breast Oncology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641 Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Furukawa
authors.affiliation: Division of Pathology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641 Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ikeda
authors.affiliation: Division of Pathology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641 Japan.
authors.forename: Seiko
authors.initials: S
authors.lastname: Kitamura
keywords: Breast cancer; Intrinsic subtype; Magnetic resonance imaging; Neoadjuvant chemotherapy