Fatemeh Jalali - Zist Fanavari Novin Biotechnology Department, State Technical and vocational Training Organization, Isfahan, Iran
Fatemeh Hamidifar - Zist Fanavari Novin Biotechnology Department, State Technical and vocational Training Organization, Isfahan, Iran
Pegah Javid - Zist Fanavari Novin Biotechnology Department, State Technical and vocational Training Organization, Isfahan, Iran
Mansoureh Azadeh - Zist Fanavari Novin Biotechnology Department, State Technical and vocational Training Organization, Isfahan, Iran

Breast cancer is the most common cancer in women. Due to the limitations of common cancer diagnostictests, the introduction of biomarkers with higher specificity for the diagnosis of breast cancer is important[reference]. The aim of this study was to evaluate the bioinformatics of HER۲-positive breast cancer and theresistance mechanisms in this disease caused by the mir-۸ family expression. The study was done throughgenomics databases. The NCBI database was used to search for HER family genes in intracellular signalingpathways. Drug targets for HER۲ were then assessed using the GeneCards database. Finally, the role of themir-۸ family in the pathogenesis of HER۲ was determined using the MirBase database. According to the dataobtained from the NCBI database, the HER family including EGFR (HER۱/ErbB۱), HER۲ (ErbB۲), HER۳(ErbB۳), HER۴ (ErbB۴), and IGF-IR can activate several oncogenic signaling pathways to stimulate growth.According to GeneCards database, HER۲ inhibitor drugs such as trastuzumab, pertuzumab, margotosumabor T-DM۱ can be used for suppression of cell growth in the treatment of this cancer. These drugs block theRas and PI۳K/mTOR pathway and prevent cell division. Trastuzumab, as a HER۲ antagonist, is one of theapproved drugs for this cancer. The miRBase database showed that downregulation of mir۱۴۱ in cancer cellshas led to resistance to the drug. In addition, the miR-۲۰۰c /۱۴۱ cluster, both of which belong to the mir-۸family, plays an important role in the epithelial to mesenchymal transition (EMT) process. The expression ofthese two miRNAs is inversely correlated with HER۲-positive breast cancer. Mir۱۴۱ plays a prominent roleas a metastasis suppressor gene. It is concluded that members of the miR-۸ family by targeting HER۲involved in the growth and processes involved in breast cancer could possibly be investigated as diagnosticbiomarkers in future studies.

Key words: HER family genes; Mir۱۴۱; miR-۲۰۰c; suppressive drugs