title: Non-canonical NF-κB pathway activation predicts outcome in borderline oestrogen receptor positive breast carcinoma.
abstract: NF-κB signalling appears deregulated in breast tumours. The purpose of this study was to determine whether the non-canonical NF-κB pathway, is activated in oestrogen receptor positive (ER+) breast cancer, to identify any correlation between its activity and the clinico-pathological phenotype and to explore whether NF-κB2 and RelB subunits and/or any of their target genes might be used as a predictive marker.
  
  
  
  Two independent cohorts of ER+ early breast cancer patients treated with adjuvant endocrine therapy were included in the study. Activation of RelB and NF-κB2 subunits was determined in a training set of 121 patients by measuring DNA-binding activities in nuclear extracts from fresh frozen specimens by an ELISA-based assay. Samples of 15 ER- breast cancer patients were also included in the study. In a large validation cohort of 207 patients, nuclear immunostaining of RelB and NF-κB2 on formalin-fixed paraffin-embedded specimens was performed. Statistical correlation within clinico-pathological factors, disease-free survival (DFS) and overall survival (OS) was evaluated. Publicly available gene expression and survival data have been interrogated aimed to identify target genes.
  
  
  
  Activation of NF-κB2 and RelB was found in 53.7 and 49.2% of the 121 ER+ tumours analysed, with similar levels to ER- breast tumours analysed in parallel for comparisons. In the validation cohort, we obtained a similar proportion of cases with activation of NF-κB2 and RelB (59.9 and 32.4%), with a 39.6% of co-activation. Multiplexing immunofluorescence in breast cancer tissue confirmed an inverse spatial distribution of ER with NF-κB2 and RelB nuclear expression in tumour cells. Interestingly, NF-κB2 and RelB mRNA expression was inversely correlated with ER gene (ESR1) levels (P<0.001, both) and its activation was significantly associated with worse DFS (P=0.005 and P=0.035, respectively) in ER+ breast cancer. Moreover, the co-activation of both subunits showed a stronger association with early relapse (P=0.002) and OS (P=0.001). Finally, higher expression of the non-canonical NF-κB target gene myoglobin was associated with a poor outcome in ER+ breast cancer (DFS, P<0.05).
  
  
  
  The non-canonical NF-κB pathway activation is inversely associated with oestrogen receptor expression in ER+ breast cancer and predicts poor survival in this subgroup. The myoglobin gene expression has been identified as a possible surrogate marker of the non-canonical NF-κB pathway activation in these tumours.
authors.affiliation: Pathology Department, IIS-Fundación Jiménez Díaz, 28040 Madrid, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Rojo
authors.affiliation: Research Unit on Biomedical Informatics-GRIB, IMIM 08003 Barcelona, Spain.
authors.forename: Abel
authors.initials: A
authors.lastname: González-Pérez
authors.affiliation: INCLIVA Biomedical Research Institute, 46010 Valencia, Spain.
authors.forename: Jessica
authors.initials: J
authors.lastname: Furriol
authors.affiliation: Pathology Department Hospital General Universitario de Castellón, 12004 Castellón, Spain.
authors.forename: Ma Jesús
authors.initials: MJ
authors.lastname: Nicolau
authors.affiliation: INCLIVA Biomedical Research Institute, 46010 Valencia, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: Ferrer
authors.affiliation: Pathology Department, Hospital Clinico Universitario, 46010 Valencia, Spain.
authors.forename: Octavio
authors.initials: O
authors.lastname: Burgués
authors.affiliation: Cancer Research Program, IMIM (Hospital del Mar Research Institute), 08003 Barcelona, Spain.|Medical Oncology Department, Hospital del Mar, 08003 Barcelona, Spain.
authors.forename: MohammadA
authors.initials: M
authors.lastname: Sabbaghi
authors.affiliation: Cancer Research Program, IMIM (Hospital del Mar Research Institute), 08003 Barcelona, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: González-Navarrete
authors.affiliation: Pathology Department, IIS-Fundación Jiménez Díaz, 28040 Madrid, Spain.
authors.forename: Ion
authors.initials: I
authors.lastname: Cristobal
authors.affiliation: Cancer Research Program, IMIM (Hospital del Mar Research Institute), 08003 Barcelona, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Serrano
authors.affiliation: Pathology Department, IIS-Fundación Jiménez Díaz, 28040 Madrid, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Zazo
authors.affiliation: Pathology Department, IIS-Fundación Jiménez Díaz, 28040 Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Madoz
authors.affiliation: Cancer Research Program, IMIM (Hospital del Mar Research Institute), 08003 Barcelona, Spain.|Medical Oncology Department, Hospital del Mar, 08003 Barcelona, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Servitja
authors.affiliation: Cancer Research Program, IMIM (Hospital del Mar Research Institute), 08003 Barcelona, Spain.|Medical Oncology Department, Hospital del Mar, 08003 Barcelona, Spain.
authors.forename: Ignasi
authors.initials: I
authors.lastname: Tusquets
authors.affiliation: Cancer Research Program, IMIM (Hospital del Mar Research Institute), 08003 Barcelona, Spain.|Medical Oncology Department, Hospital del Mar, 08003 Barcelona, Spain.|Universitat Pompeu Fabra, 08002 Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Albanell
authors.affiliation: INCLIVA Biomedical Research Institute, 46010 Valencia, Spain.|Oncology and Hematology Department, Hospital Clinico Universitario, 46010 Valencia, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Lluch
authors.affiliation: Cancer Research Program, IMIM (Hospital del Mar Research Institute), 08003 Barcelona, Spain.|Medical Oncology Department, Hospital del Mar, 08003 Barcelona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Rovira
authors.affiliation: INCLIVA Biomedical Research Institute, 46010 Valencia, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Eroles
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000378:metabolism*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism*; D011379:Prognosis; D011960:Receptors, Estrogen / Q000378:metabolism*
chemical_list: D016328:NF-kappa B; D011960:Receptors, Estrogen