A Clinical Evaluation of Circulating MiR-106a and Raf-1 as Breast Cancer Diagnostic and Prognostic Markers.

Objective: MicroRNAs (MiRNAs) regulate mammalian cell growth, differentiation, and apoptosis by altering the expression of other genes and serve multiple roles in tumorigenesis and progression. Proto-oncogene serine/threonine-protein kinase (RAF-1) functions as a part of the MAPK/ERK signal transduction pathway. The present study aim was to prospectively evaluate MicroRNA 106a (MiR-106a) and RAF-1 as a diagnostic and prognostic factor in early prediction of breast cancer (BC), recurrence and early detection of distant metastasis as well as to analyses the statistical correlation between MiR-106a and RAF-1 levels and clinical-pathological parameters including tumor size, lymph node, histological type and grading.

Methods: Sera and plasma of 30 normal women and 50 women with breast carcinoma were assayed for MiR-106a by RT-qPCR as well as levels of Hb, WBCs and platelets count and RAF-1 by solid phase enzyme-linked immunosorbent assay (ELISA).

Results: The patients' characteristics, they were classified according to grade into 8% grade I, 66% grade II, 22% grade III and 4% grade IV. The stages were classified according to the TNM system as stage II was the highest percentage 66%, while the lowest percentage was 10% for stage I and 24% for stage III. Also, Hb% and RAF-1 levels were significantly decreased in breast cancer patients as compared with healthy control. On the other hand, MiRNA-106a gene expression was non-significantly increased in positive lymph node metastasis patients (FC=3.66) when compared to patients with negative lymph node metastasis (FC=3.51). In addition, MiR-106a was significantly up-regulated in breast cancer patients with a fold of change 3.63 when compared to control samples.

Conclusion: Expression of MiR-106a gene can be used as a diagnostic and prognostic noninvasive biomarker which can stimulates breast cancer cell invasion and proliferation through downregulation of Raf-1 levels.
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