Up-regulation of cell free plasma miR-106b as a possible prognostic marker in breast cancer

Breast cancer is the most prevalent cancer in women worldwide and often has the ability to undergo metastasis .PTEN is a tumor suppressor gene located on human chromosome 10 and is widely confirmed as one of the most frequently deleted or mutated genes in various human tumors. PTEN could inhibit PI3K/Akt signaling via antagonizing the function of PI3K by reversing the phosphorylation of PIP3 to PIP2. Reduced PTEN expression levels correlate with aggressive breast cancer phenotype and poor prognosis. miRNAs are small, endogenous, non-coding RNAs negatively regulate the target messenger RNAs (mRNAs) by acting on the 3 -untranslated regions (3 UTRs) of the target genes via repression of protein translation or inducing mRNAs degradation. MicroRNA 106b (miR-106b) is located in a cluster with miRs 93–25 on intron 13 of the Mcm7 on chromosome 7q22. As a target gene for miR-106b, the expression of PTEN is negatively regulated by miR-106b, thus affecting multiple biological functions of tumor cells. Here, level of miR-106b expression in tumour and blood plasma of breast cancer patients were compared with normal control using comparative Real-time RT-PCR method. Results: Our data showed that the expression of miR-106b in breast tumors is significantly higher than normal tissues which is related to the stage of tumors and the status of tumor hormonal receptors. That phenomenon were concordantly detected in plasma. Discussion: We can conclude that up regulation of miR-106b may be considered as a possible prognostic marker which is detectable in blood via Inhibition of PTEN . confirmation of this phenomenon may be promising in breast cancer management.