The Impact of miRNAs on the Efficacy of Tamoxifen in Breast Cancer Treatment: A Systematic Review.

Seventy percent of breast cancer patients have an active estrogen receptor. Tamoxifen interferes with estrogen's ability to bind to cancer cells. The most challenging aspect of tamoxifen, however, is that breast cancer cells become resistant to its effects. Some studies have shown that alterations in miRNA expression contribute significantly to drug resistance in breast cancer. Therefore, the present systematic review aims to investigate miRNAs that significantly influence the response to tamoxifen treatment. The present study follows the PRISMA instructions. The Web of Science, PubMed, and Scopus databases were searched to retrieve English articles. The searches were conducted up to September 11, 2022. The search strategy included the terms "Tamoxifen", "Breast Neoplasm", and "MicroRNA". The inclusion criteria of this study are English, original, and experimental studies investigating miRNAs that are effective in the treatment efficacy of tamoxifen. A total of 565 articles were retrieved. After screening, 75 studies met our inclusion criteria. This systematic review study examined 105 miRNAs, of which 44 have a positive effect, and 47 miRNAs inhibit tamoxifen function. Fourteen miRNAs have a controversial effect, ie, some studies show positive and negative effects. The study of miRNAs affecting tamoxifen function in breast cancer patients may facilitate the identification of individuals at higher risk of disease recurrence. Conversely, it can potentially utilize appropriate interventions to defeat drug resistance effectively.

Unveiling the Potential of Serum MiR-483-5p: A Promising Diagnostic and Prognostic Biomarker in OLP and OSCC Patients by In silico Analysis of Differential Gene Expression.

BACKGROUND: Oral squamous cell carcinoma (OSCC) and oral lichen planus (OLP) are two separate conditions affecting the mouth and result in varying clinical outcomes and levels of malignancy. Achieving early diagnosis and effective therapy planning requires the identification of reliable diagnostic biomarkers for these disorders. MicroRNAs (miRNAs) have recently received attention as powerful biomarkers for various illnesses, including cancer. In particular, miR-483-5p is a promising diagnostic and prognostic biomarker in various cancers. Therefore, this study aimed to investigate the role of serum miR-483-5p in the diagnosis and prognosis of OLP and OSCC patients by in silico analysis of differential gene expression. METHODS: GSE23558 and GSE52130 data sets were selected, and differential gene expression analysis was performed using microarray data from GSE52130 and GSE23558. The analysis focused on comparing OLP and OSCC samples with normal samples. The genes intersected through the differential gene expression analysis were then extracted to determine the overlapping genes among the upregulated or downregulated DEGs. The downregulated genes among the DEGs were subsequently imported into the miRWalk database to search for potential target genes of miRNA 483-5p that lacked validation. To gain insight into the biological pathways associated with the DEGs, we conducted pathway analysis utilizing tools, such as Enrichr. Additionally, the cellular components associated with these DEGs were investigated by analyzing the String database. On the other hand, blood serum samples were collected from 35 OSCC patients, 34 OLP patients, and 34 healthy volunteers. The expression level of miR-483-5p was determined using quantitative reverse transcription polymerase chain reaction (RT-qPCR). The Kruskal-Wallis test was utilized to investigate the considerable correlation. Moreover, this study explored the prognostic value of miR-483-5p through its association with clinicopathological parameters in OSCC patients. RESULTS: The results showed that serum expression of miR-483-5p was considerably higher in OSCC patients compared to OLP patients and healthy controls (p 0.0001) and that this difference was statistically significant. Furthermore, elevated miR-483-5p expression was associated with tumor size, lymph node metastasis, and stage of tumor nodal metastasis in OSCC patients (p 0.001, p 0.038, and p 0.0001, respectively). In silico analysis found 71 upregulated genes at the intersection of upregulated DEGs and 44 downregulated genes at the intersection of downregulated DEGs, offering insight into the potential underlying mechanisms of miR-483-5p's engagement in OSCC and OLP. The majority of these DEGs were found to be involved in autophagy pathways, but DEGs involved in the histidine metabolism pathway showed significant results. Most of these DEGs were located in the extracellular region. After screening for downregulated genes that were invalidated, miRNA 483-5p had 7 target genes. CONCLUSION: This study demonstrates the potential of serum miR-483-5p as a promising diagnostic and prognostic biomarker in OSCC and OLP patients. Its upregulation in OSCC patients and its association with advanced tumor stage and potential metastasis suggest the involvement of miR-483-5p in critical signaling pathways involved in cell proliferation, apoptosis, and cell cycle regulation, making it a reliable indicator of disease progression. Nevertheless, additional experimental studies are essential to validate these findings and establish a foundation for the advancement of targeted therapies and personalized treatment approaches.