| Breast cancer is the most common cause of cancer-related death among women in the whole world. MiR-
34a and let-7a are well known tumor suppressors that participate in the regulation of apoptosis, invasion and
other cellular functions. In this study, expression of miR-34a, let-7a and apoptosis pathway genes such as Bcl-2,
Caspase-3 and P53 were evaluated using quantitative real-time PCR in 45 paired samples of normal margin
and tumor tissue collected from breast cancer patient at advanced stage (3-4). MiR-34a, let-7a, caspase-3 and
P53 expression are reduced and Bcl-2 expression is increased within tumoral tissues in comparison with normal
margin tissues. P53 expression directly or indirectly was correlated with miR-34a, let-7a, Bcl-2 and caspase-3
expression. In This study we found that MiR-34a and let-7a expression are reduced in the tumoral tissues. Downregulation
of these two molecules correlated with expression of genes associated with apoptosis. These results
suggest that due to the correlation of miR-34a and let-7a with apoptotic and anti-apoptotic pathways these
molecules could participate as regulators in advanced clinical stages of breast cancer and should be considered
as markers for diagnosis, prognostic assessment and targeted therapy. |