The Diagnostic Potential of miRNAs in Lebanese Renal Cell Carcinoma Patients: A Histological and Molecular Perspective

Abstract

Background: Renal cell carcinoma (RCC) is the seventh (2.2%) and the tenth (1.8%) most frequent cancer worldwide in men and women, respectively. In Lebanon, it ranks as the tenth most common cancer in men and the nineteenth in women. However, unlike the global average where the most prevalent subtype is clear cell RCC (ccRCC), papillary RCC (pRCC) has higher incidence in Lebanon. This histological variation emphasizes the need to conduct further research on the matter. Deregulation of micro-RNAs (miRNAs) is emerging as a major aspect of cancer etiology. This current study is undertaken to characterize the miRNA expression profiles of RCC patients from Lebanon. Towards that end, our aim was to characterize retrospectively the histopathology of RCC samples collected from 2018 till 2024 at AUBMC. We also performed a literature review of the most differentially dysregulated miRNAs in RCC as well as an in-silico analysis of the miRNA dysregulation in RCC in The Cancer Genome Atlas (TCGA) to identify a miRNA signature for RCC as compared to normal tissues. We finally validated the dysregulated expression of the selected miRNAs in RCC samples from Lebanese patients. This study offers the promise of explaining the peculiarities of RCC in Lebanon and ultimately identifying novel biomarkers for diagnosis and/or prognosis of this disease. Methods and Methods: After securing the ethical approval, a retrospective study of patient demographics and histopathological characteristics was performed. A crosscomparison between the literature review and the in-silico study was performed to identify the most commonly dysregulated miRNAs in RCC. Paraffin embedded (FFPE) tissue samples from ccRCC and pRCC patients with matched non-neoplastic tissues were collected for miRNA profiling. Total RNA was isolated using the RNeasy FFPE DSP kit, and RNA quality was confirmed using a Denovix Nanodrop spectrophotometer. Ten nanograms of RNA were reverse-transcribed using the miRCURY LNA RT Kit, followed by quantification with miRCURY LNA SYBR Green PCR Assays. Fold changes between tumor and normal tissues were calculated using the ∆∆Ct method. A melt curve (60–95°C) ensured specificity of amplification. Diagnostic potential was evaluated using ROC curves and logistic regression to identify single and combined miRNAs with discriminatory value. Results and Conclusion: Our results showed that several miRNAs were significantly dysregulated in tumor tissue versus matched adjacent normal tissue, notably miR-21-5p, miR-210-3p, miR-34a-5p, and miR-222-3p were upregulated. A combined panel of top candidates discriminated tumor from normal with high accuracy (combined AUC = 3 0.911). Despite advances in detection and therapies, RCC remains a significant challenge in oncology due to its complex nature and diverse subtypes. To our knowledge, this is the first study directly investigating miRNA in Lebanese RCC patients. In conclusion, this study helps identifying miRNA expression patterns predicting diagnosis and potentially explaining the peculiarities of RCC in Lebanon.