289P - Prognostic significance of immunohistochemical subtyping and PAM50 intrinsic subtypes in male breast cancer (MaBC)

Date 10 October 2016
Event ESMO 2016 Congress
Session Poster display
Topics Breast Cancer, Metastatic
Pathology/Molecular Biology
Presenter Martina Alvarez
Citation Annals of Oncology (2016) 27 (6): 68-99. 10.1093/annonc/mdw365
Authors M. Alvarez1, A. Sanchez-Muñoz2, A. Santonja2, Y. Plata Fernández3, J. Miramón4, I. Zarcos Pedrinaci5, C. Llacer6, V. de Luque7, M.J. Lozano León8, J.M. Jerez8, L. Pérez Villa8, R. Lavado2, C. Ramirez9, A. Jiménez10, I. Rodrigo6, E. García11, L. Vicioso8, E. Alba Conejo2
  • 1Pathology, Biomedical Research Institute of Málaga (IBIMA), 29071 - Malaga/ES
  • 2Medical Oncology, Biomedical Research Institute of Málaga (IBIMA), Malaga/ES
  • 3Oncology, Complejo Hospitalario de Jaen Universidad de Jaen, 23007 - Jaen/ES
  • 4Medical Oncology, Hospital de la Serrania, Ronda (Málaga)/ES
  • 5Oncology, A.S Hospital Costa del Sol, 29603 - Malaga/ES
  • 6Servicio De Oncología Médica, Hospital Regional Universitario Carlos Haya, Malaga/ES
  • 7Medical Oncology, iomedical Research Institute of Malaga (IBIMA)-Hospital Universitario Regional y Virgen de la Victoria, Malaga, Malaga/ES
  • 8Pathology, Biomedical Research Institute of Málaga (IBIMA), Malaga/ES
  • 9Pathology Department, Complejo Hospitalario de Jaen Universidad de Jaen, Jaen/ES
  • 10Pathology Department, Hospital Regional Universitario Carlos Haya, Malaga/ES
  • 11Pathology Department, Hospital de la Serrania, Ronda (Málaga)/ES

Abstract

Background

Substantial controversy exists about the prognostic role of molecular tumor subtypes in MaBC. It is mainly classified as a luminal disease, but survival differences between Luminal A and B are not clarified. The aim of this study was to assess the molecular subtype profiles of MaBC, and subsequently the clinical outcome, using two different approaches: mmunochemistry and the gene-expression profile PAM50.

Methods

A total of 69 cases of invasive MaBC, were examined using an immunohistochemical standard staining for estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), human epidermal growth factor receptor 2 (HER2), cytokeratin 5/6 (CK5/6), epidermal growth factor receptor (EGFR) and Ki-67. Immunohistochemical subtypes were classified according to Cheang et al. (2009). Gene-expression profiling was performed on a research-use-only (RUO) nCounter Analysis System using the RUO PAM50 assay analyzed with the Prosigna® algorithm. The Kaplan-Meier method was used to estimate Overall Survival (OS).

Results

Patients had a median age of 63 (range 23-92). The mean and median OS were 184 and 156 months, respectively. At diagnosis, patients were mainly stage I (27.5%) and II (40.6%). When subtyping by IHQ and PAM50, the majority of samples were luminal B (49.3% and 59.7%, respectively) followed by luminal A (44.3% and 29.9%). Only 5.8% by IHQ and 10.4% by PAM50 were non-luminal (1 basal-like, 2 non-basal triple negative and 1 Her2-enriched by IHQ and 7 Her2-enriched by PAM50). We found a strong association between both IHQ and PAM50 classifications (p-value = 0.007). There were no significant differences in OS between luminal A and luminal B subtypes, neither by immunohistochemistry (p = 0.22) nor in PAM50 subtypes (p = 0.89). However, Her2-enriched patients by PAM50 showed significant worse prognosis (p = 0.009).

Conclusions

The most common subtypes in our MaBC cohort were luminal B followed by luminal A. No differences were found between these tumor subtypes in terms of patient outcome. However, Her2-enriched patients by PAM50 showed worse prognosis. Further research with larger cohorts is needed to unveil the real role of the different subtypes in MaBC.

Clinical trial identification

Legal entity responsible for the study

Biomedical Research Institute of Malaga (IBIMA)-Hospital Universitario Regional y Virgen de la Victoria, Malaga (Spain)

Funding

FIMABIS

Disclosure

All authors have declared no conflicts of interest.