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Abstract
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Introduction: Breast cancer is the most common cancer in females which is also considered as a heterogeneous disease
having significant molecular variation. Long non-coding RNAs (lncRNA) are a group of non–coding transcripts longer
than 200 nucleotides, that have been shown to play important regulatory roles in cancer biology. One of lncRNAs that has
attracted significant attention is HOTAIR (HOX transcript antisense intergenic RNA), that is transcripted from a 2.2 kb
gene located in the HOXC locus on chromosome 12q13.13. HOTAIR has been identified as an oncogenic lncRNA that
plays important regulatory roles in variety of human cancers. This lncRNA is associated with the Polycomb Repressive
Complex 2 (PRC2). The HOXD locus on chromosome 2 is a PRC2 target. HOTAIR causes the transcriptional silencing
of a 40 kb region of the HOXD locus which remodels the gene expression pattern of cells and reprograms chromatin state
to promote cancer metastasis. Moreover, HOTAIR is significantly up-regulated in most tumor tissues and can be considered
as a potential cancer biomarker for diagnosis and prognosis. The aim of this study was to examine the expression
of HOTAIR in breast cancer. Methods: Total RNA was isolated from fresh tissue specimens using the RNX- Plus kit.
We examined the relative expression of HOTAIR in breast cancer tissues in comparison to adjacent noncacerous tissues
using quantitative Real-Time PCR (qRT-PCR). β2m (Beta-2-microglobulin) was used as a reference gene. The results
were analyzed for correlation with the clinical parameters. Results: The results demonstrate that HOTAIR expression in
breast cancer tissues was significantly upregulated compared to noncancerous tissues. Increased HOTAIR expression was
significantly correlated with, TNM staging, and distant metastasis. Moreover, According to the HOTAIR expression level
in primary breast tumors we can predict final metastasis and death.
Conclusions: Our findings indicate that HOTAIR expression is modulate
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