The study of long noncoding RNA, MEG3, expression level and its association with clinicopathologic features in breast cancer

Breast cancer is the most common invasive cancer and the second main cause of cancer death in women. Long noncoding RNAs (lncRNAs) play a critical role in different cellular and molecular activities such as carcinogenesis. Maternally Expressed Gene 3 (MEG3), is a long noncoding RNA that deregulates in various types of cancers. The aim of this study is the evaluation of MEG3 expression level and its association with clinicopathological features of breast tumor tissues.
In this case-control study, 40 fresh-frozen breast tumor specimens and their paired non-tumoral adjacent tissues were collected from breast cancer patients living in the northwestern region of Iran. All tumor samples belonged to the invasive ductal carcinoma. After RNA extraction and cDNA synthesis, the expression level of MEG3 in breast tumor tissues compared to the paired adjacent normal tissues was investigated using specific primers and quantitative real-time PCR (qRT-PCR). β2m was also used as an internal control for normalization.
Findings: MEG3 expression level in all tumor samples significantly downregulated compared to the paired adjacent nontumoral specimens, with an average fold decrease of 3.355 (p=0/042). Low level of MEG3 in tumor tissues was also related to the age of patients (p=0/007), stage Ⅲ (p=0/049) and lymph node metastasis (p=0/018).
The expression level of MEG3 significantly decreased in breast cancer and this downregulation was related to malignancy state of the tumor.