Diagnostic and Prognostic Value of MicroRNA as a Potential Biomarker in Breast Cancer Patients in Correlation to Radiological Findings.

Breast cancer ( BC) is the most commonly diagnosed cancer in women worldwide. The incidence and mortality rates for female breast cancer far exceeded those for other cancers . Although the incidence rate of breast cancer has risen, the mortality rates have steadily fallen due to early diagnosis and better treatments . Early detection of breast cancer often leads to better outcomes. According to Cancer Australia's National Cancer Control Indicators, the relative survival for females diagnosed with early-stage breast cancers at diagnosis was much higher than that for those with advanced breast diagnosis.

Despite the improvement in diagnosis and treatment,approximately 20% of BC patients will develop metastasis.This setting is considered an incurable disease that often occurs due to either resistance to therapy or diagnosis at advanced stages . In this scenario, although 44% of the patients are diagnosed at stage I (AJCC cancer staging) with 5-year survival rates of 100%, 5% of patients are diagnosed at stage IV with 5-year survival rates of approximately 26% .

The small percentage of women diagnosed at advanced stage of the disease gives evidence that mammography represents the best available screening option for breast cancer .

However, more accurate and meaningful early-diagnosis methods together with image techniques would improve BC survival rates.

MicroRNAs (MiRNAs) are short endogenous noncoding RNA molecules of 19-25 nt that have important gene regulatory roles at post-transcriptional level [8, 9]. They pair with messenger RNAs (mRNAs) of protein-coding genes and depending on complementarity, leading to mRNa translational repression or degradation . They regulate 30% of transcripts and contain 3% of the human genome .