Relapse-free survival in breast cancer patients is associated with a gene expression signature characteristic for inflammatory breast cancer.
OBJECTIVE
We hypothesize that a gene expression profile characteristic for inflammatory breast cancer (IBC), an aggressive form of breast cancer associated with rapid cancer dissemination and poor survival, might be related to tumor aggressiveness in non-IBC (nIBC).


METHODS
RNA from 17 IBC samples and 40 nIBC samples was hybridized onto Affymetrix chips. A gene signature predictive of IBC was identified and applied onto 1,157 nIBC samples with survival data of 881 nIBC samples. Samples were classified as IBC-like or nIBC-like. The IBC signature classification was compared with the classifications according to other prognostically relevant gene signatures and clinicopathologic variables. In addition, relapse-free survival (RFS) was compared by the Kaplan-Meyer method.


RESULTS
Classification according to the IBC signature is significantly (P < 0.05) associated with the cell-of-origin subtypes, the wound healing response, the invasive gene signature, the genomic grade index, the fibroblastic neoplasm signature, and the 70-gene prognostic signature. Significant associations (P < 0.01) were found between the IBC signature and tumor grade, estrogen receptor status, ErbB2 status, and patient age at diagnosis. Patients with an IBC-like phenotype show a significantly shorter RFS interval (P < 0.05). Oncomine analysis identified cell motility as an important concept linked with the IBC signature.


CONCLUSIONS
We show that nIBC carcinomas having an IBC-like phenotype have a reduced RFS interval. This suggests that IBC and nIBC show comparable phenotypic traits, for example augmented cell motility, with respect to aggressive tumor cell behavior. This observation lends credit to the use of IBC to study aggressive tumor cell behavior.
Van Laere
Steven
S
Translational Cancer Research Group, Laboratory of Pathology, University of Antwerp and Oncology Center, General Hospital Sint-Augustinus, Wilrijk, Belgium.
Beissbarth
Tim
T
Van der Auwera
Ilse
I
Van den Eynden
Gert
G
Trinh
Xuan Bich
XB
Elst
Hilde
H
Van Hummelen
Paul
P
van Dam
Peter
P
Van Marck
Eric
E
Vermeulen
Peter
P
Dirix
Luc
L
D000367:Age Factors; D001943:Breast Neoplasms / Q000235:genetics* / Q000401:mortality* / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D016130:Immunophenotyping; D053208:Kaplan-Meier Estimate; D008297:Male; D010641:Phenotype; D011379:Prognosis; D012680:Sensitivity and Specificity