Expression analysis of vimentin and the related lncRNA network in breast cancer

Vimentin (VIM) is a mesenchymal marker which is expressed in some cancer types including breast cancer. A long non-coding RNA (lncRNA) has been identified to be transcribed from VIM gene locus and positively regulate expression of VIM. This lncRNA has been named as VIM-antisense 1 (VIM-AS1). Expression of VIM is also regulated by another lncRNA namely AGAP2-antisense RNA 1 (AGAP2-AS1). In the current study, we aimed at identification of the expression pattern of VIM, VIM-AS1, AGAP2 and AGAP2-AS1 in 78 breast cancer samples and their paired adjacent non-cancerous tissues (ANCTs) by means of real time PCR. All mentioned genes were significantly down-regulated in tumoral tissues compared with ANCTs (P values less than 0.000). Relative expression of VIM-AS1 in tumoral tissues versus ANCTs was associated with menopause age (P = .02) in a way that this gene was down-regulated in most of patients whose menopause age was between 40 and 50 years. Moreover, AGAP2-AS1 relative expression was associated with patients' body mass index (P = .03). There were trends toward association between VIM relative expression and tumor size (P = .07) and association between VIM-AS1 relative expression and obesity (P = .06). Expression of VIM was significantly higher in tumoral tissues of patients who had history of hormone replacement therapy compared with those without such history (P = .03). Moreover, expression levels of both VIM and AGAP2-AS1 were lower in patients whose menarche age was between 10 and 12 years old compared with those whose menarche age was between 13 and 15 years old (P values = .01 and 0.04, respectively). Transcript quantities of VIM, VIM-AS1, AGAP2 and AGAP2-AS1 were correlated with each other both in tumoral tissues and in ANCTs. Among four assessed genes, AGAP2 had the best diagnostic power for discrimination of tumoral tissues from ANCTs (AUC value = 0.87). Combination of four genes led to enhancement of AUC value to 0.94. The current study shows the importance of VIM and its associated lncRNAs in breast cancer and potentiates these genes as biomarkers for this malignancy. Moreover, these lncRNAs might be regarded as therapeutic targets in breast cancer.