Circulating LncRNAs as predictive biomarkers by molecular subtypes in advanced breast tumors.
e23041 Background: Breast cancer is the most common malignant tumor in women worldwide. The leading breast cancer deaths are due to advanced disease stage. For this reason, identification of novel breast cancer progression-associated biomarkers would enhance the clinical management of each patient. Long non-coding RNAs (LncRNAs) are defined as noncoding RNAs longer than 200 nucleotides and are involved in several regulatory processes, such as regulation of gene expression. Moreover, it has been described that LncRNA expression is deregulated in different human diseases such as breast cancer. However, it is unclear if circulating LncRNAs could be used as progression biomarkers of breast cancers. The purpose of this study was to evaluate the role of circulating LncRNAs in patients with advanced breast cancer. Methods: Expression of 84 LncRNAs was quantified by “RT2 IncRNA PCR Array Human Cancer PathwayFinder” (Qiagen) in plasma from 24 subjects (12 patients with advanced breast cancer and 12 healthy subjects). cDNAs were pooled into four groups, two groups containing a mixture of six patients with advanced breast cancer and another two groups containing a mixture of six cDNAs from healthy subjects. Three differentially expressed LncRNAs were selected for validation by specific real-time PCR assay. Results: Three deregulated LncRNAs were identified and validated in patients with advanced breast cancer versus healthy subjects. We found that LncRNAs GAS5 and ZFAS1 expression was decreased in the Luminal, Her2-positive and Triple Negative advance cancer groups compared to healthy subjects. In contrast, LncRNA RMRP expression was increased in Luminal and Her2-positive advance cancer groups. To our knowledge, there are no publications relating the LncRNA RMRP expression with advance breast cancer research. Conclusions: These results contribute to unreveal the role of circulating LncRNAs as biomarkers in the advanced breast cancer and provide novel non-invasive tools in this disease.