A New Pirna-Based Biomarker For the Her2 Status in Breast Cancer

Background and aim: breast cancer is the most common leading cause of cancer deaths in women worldwide. it is classified into four molecular subgroups based on the presence of estrogen and progesterone hormone receptors and human epidermal growth factor receptors. each subtype manifests different prognosis, aggression and response to available therapies. trastuzumab, an anti-her2 antibody, is used for breast cancer treatment in patients with her2 overexpression or gene amplification. since this drug is specific to one subtype of breast cancer, determining the subtype is critical in disease management. current methods for detecting the her2 amplification status are not completely efficient so it seems that introducing a new method is necessary. small non-coding rnas are stable and detectable in biological fluids, thus they can be good biomarker candidates. therefore, the first step of our study was to search for small ncrnas within the region that co-amplified with her2.methods: in this study, we first performed bioinformatics analysis for the expression of a pirna within the her2 (which we called herpir) in three mirseq datasets (gse68085, gse56134 and e-mtab-4539). to confirm bioinformatics results, her2 positive and negative breast cancer tumour specimens were collected. rna was extracted and probed using herpir probe and the herpir concentration was assessed.results: the results of mirseq datasets analysis demonstrated a significant difference in the level of herpir between positive and negative her2 samples and its expression elevated in her2+ and ihc+3 samples. the results of herpir expression analysis in tissue samples also confirm these results and indicate a very significant difference of herpir level with p-value < 0.0001 between her2 positive and negative samples.conclusion: to evaluate the ability of this pirna to identify her2 status of tumours as a sensitive biomarker, roc curve was plotted. based on the bioinformatics and experimental results and area under the roc curve (auc) which was 1, it can be claimed that herpir can be an accurate and sensitive biomarker to determine her2 status of tumours.