Background: Breast cancer (BC) is known as the most prevalence type of cancer among women. Trastuzumab, as a cancer drug, has been used broadly in human epidermal growth factor receptor 2 (HER-2) positive BC patients. On the other hand, accumulating evidence has demonstrated that microRNAs involved in pathogenesis BC. Hence, we aimed to investigate the effect of trastuzumab on the expression levels of microRNA-26a in HER-2positiveBC patients.

Methods: This study was conducted on HER-2 positive BC patients and HER-2 Negative BC patients. Serum expression of microRNA-26a were detected by real-time PCR. Then, we assessed the correlation of microRNA-26a level with multiple clinico-pathological characteristics.

Results: In HER-2 positive patients, the microRNA-26a expression significantly increased after treatment with Docetaxel/Trastuzumab in comparison to before treatment (p.value= 0.01). However, this overexpression in HER-2 negative patients after treatment with Docetaxel was not significant compared to before treatment (p.value=0.14). Besides, the expression microRNA -26a significantly increased in HER-2 positive patients who were ≤48 years old and premenopausal after treatment with Docetaxel/Trastuzumab when compared to before treatment (p.value=0.039, 0.031, respectively). Furthermore, there was a significant relationship between expression microRNA -26a with tumor size, stage, ER and PR status in HER-2 positive group before and after treatment (p.value=0.043, 0.042, 0.049 and 0.034 respectively).

Conclusions: Trastuzumab led to overexpression of microRNA-26a in HER-2 positive BC patients. It seems that detecting microRNA -26a during trastuzumab therapy could be useful as a factor for monitoring in BC patients.

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.