Breast cancer (BC) is the leading cause of cancer‐related mortality in the female population. MicroRNA‐155 (miR‐155), an oncogenic non‐coding RNA, plays an important role in the pathogenesis of breast cancer. However, the level of circulating miR-155 expression and its clinical significance are not well established. The aim of present study was to evaluate the prognostic role of circulating miR-155 expression in serum of breast cancer patients.
Study includes 75 serum samples from histopathologically confirmed, newly diagnosed cases of breast cancer and 75 healthy control subjects. Total RNA from serum was isolated by using Trizol reagent, polyadenylated and reverse transcribed into cDNA. The expression level of miR‐155 was detected by using qRT‐PCR. Relative expression was determined with matched controls using U6 snRNA as a reference. Levels of miRNA expression were compared with distinct clinicopathological features. The total follow-up period was 41 months and mean follow-up time was 28 months. Kaplan-Meier survival analysis was performed for overall survival of breast cancer patients. The study was ethically approved by Institutional Ethics Committee, Maulana Azad Medical College, New Delhi.
The overall relative fold increase of miR‐155 expression in breast cancer patients was 8.80 fold compared to the healthy controls. When the level of miR‐155 expression was compared with distinct clinicopathological features, there was a significant association seen between miR‐155 expression with TNM stage (p = <0.0001), lymph node status (p = 0.007) and distant metastasis (p = 0.001) of breast cancer patients. ROC analysis for prognosis yielded significant AUC values for early vs advanced stages (AUC= 0.742 (95% CI: 0.629-0.855)) and presence vs absence of distant metastasis (AUC= 0.913 (95% CI: 0.838-0.988)) of breast cancer patients. There was a significant association (p = 0.004) found between overall survival and expression of miR‐155 in breast cancer patients.
Our findings suggest that overexpression of serum miR‐155 expression might be a useful, non-invasive, prognostic biomarker for breast cancer patients. A large pool study will be necessary to confirm our findings.
Prof. Dr. Alpana Saxena
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All authors have declared no conflicts of interest.