Favorable outcome associated with an IGF-1 ligand signature in breast cancer.
ABSTRACT The insulin-like growth factor (IGF) axis is fundamentally important in cell growth, development and cancer. We used genomic technologies to better characterize the activity of the IGF axis in human breast cancer and to identify predictors of response to IGF targeted therapies. Analysis of the gene expression patterns and pathway analysis in 204 clinically annotated primary breast cancers were performed and compared to levels of mRNA for IGF ligands and receptors. Pathway activation scores were calculated by Pearson correlation (+1, -1). Network analysis was performed using Ingenuity software. IGF-1 ligand levels were strongly negatively correlated (P < 10⁻⁶) with a published IGF-IR activation signature.A signature of high IGF-1 ligand was associated with better prognosis (P = 0.025-1.5 x 10⁻⁸) in several public datasets. Pathway analysis revealed upregulation of pathways associated with breast differentiation (adipocyte growth factors, PPAR-gamma) and down-regulation of proliferation pathways (AKT/MAPK) in the IGF-1 ligand high group. Of note, the IGF-1 ligand signature was anti-correlated with IGFIR receptor levels (P = 0.07). In conclusion, a breast tumor-derived signature of high IGF-1 ligand is associated with favorable outcome, in contrast to a previously reported IGF-IR activation signature. The prognostic value of the IGF-I ligand signature is validated in three independent datasets. These signatures should be applied in study of IGF1-R targeted therapy.
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ABSTRACT: Large noncoding RNA HOTAIR, transcribed from the antisense strand of HOXC12, interacts with Polycomb Repressive Complex 2 (PRC2) in the regulation of gene activities. Recent work suggests that it may have effects on breast cancer progression and survival. We evaluated HOTAIR expression and the methylation status of its downstream intergenic CpG island in primary breast cancers, and examined associations of these factors with clinical and pathologic features and patient survival. HOTAIR expression and DNA methylation were analyzed in tissue from 348 primary breast cancers with quantitative RT-PCR and methylation-specific PCR, respectively. HOTAIR expression and methylation varied widely in the tissues. A positive correlation was found between DNA methylation and HOTAIR expression. Methylation was associated with unfavorable disease characteristics, whereas no significant associations were found between HOTAIR expression and clinical or pathologic features. In multivariate, but not in univariate, Cox proportional hazard regression models, patients with high HOTAIR expression had lower risks of relapse and mortality than those with low HOTAIR expression. These findings suggest that the intergenic DNA methylation may have important biologic relevance in regulating HOTAIR expression, and that HOTAIR expression may not be an independent prognostic marker in breast cancer, but needs further validation in independent studies.Breast Cancer Research and Treatment 11/2012; · 4.47 Impact Factor