MiRNA biomarkers in cancers of the male reproductive system: are we approaching clinical application?

MicroRNA-371-373 cluster extracellular vesicle-based communication in testicular germ cell tumors

Testicular germ cell tumors (TGCTs) represent the most common type of cancer in young adults. The cluster of microRNAs 371-373 is highly upregulated in TGCTs, and detection of miR-371a-3p specifically is currently being developed for clinical implementation as a sensitive and specific biomarker for TGCT, except for teratoma. Extracellular vesicles (EVs) are nano-sized particles used for cell communication, being increasingly regarded as potential sources of cancer biomarkers. Thus, the aim of this study was to characterize EVs from a wide range of TGCT samples, including cell lines, tissue explants and matched plasma samples from patients and healthy donors, and then use these samples to assess microRNA expression (miR-371-373 cluster and let-7e). TGCT-derived EVs were successfully isolated and characterized according to MISEV guidelines. TGCT cell lines showed different levels of EV-derived miR-371-373 cluster and let-7e. Upon differentiation of NT2 cells with ATRA, both cellular and EV-derived miR-371-373 cluster were downregulated, whereas let-7e was upregulated. TGCT patient samples presented high levels of EV-derived miR-371-373, except for the teratoma samples. We conclude that a significant portion of the circulating miR-371-373 cluster used as a TGCT biomarker in the clinic is secreted into EVs, and that this cluster and the let-7 family of microRNAs may be related with TGCT intercellular communication and differentiation.

Exploring the molecular pathways of miRNAs in testicular cancer: from diagnosis to therapeutic innovations

Cancer diagnostics highlight the critical requirement for sensitive and accurate tools with functional biomarkers for early tumor detection, diagnosis, and treatment. With a high burden of morbidity and mortality among young men worldwide and an increasing prevalence, Testicular cancer (TC) is a significant death-related cancer. Along with patient history, imaging, clinical presentation, and laboratory data, histological analysis of the testicular tissue following orchiectomy is crucial. Although some patients in advanced stages who belong to a poor risk group die from cancer, surgical treatments and chemotherapeutic treatment offer a high possibility of cure in the early stages. Testicular tumors lack useful indicators despite their traditional pathological classification, which highlights the need to find and use blood tumor markers in therapy. Regretfully, the sensitivity and specificity of the currently available biomarkers are restricted. Novel non-coding RNA molecules, microRNAs (miRNAs), have recently been discovered, offering a potential breakthrough as viable biomarkers and diagnostic tools. They act as fundamental gene regulators at the post-transcriptional level, controlling cell proliferation, differentiation, and apoptosis. This article aims to comprehensively explore the role of miRNAs in the pathophysiology, diagnosis, and treatment of TC, with a focus on their regulatory mechanisms within key signaling pathways such as TGF-β, PTEN/AKT/mTOR, EGFR, JAK/STAT, and WNT/β-catenin. By investigating the potential of miRNAs as diagnostic and prognostic biomarkers and therapeutic targets, this study seeks to address challenges such as treatment resistance and evaluate the clinical importance of miRNAs in improving patient outcomes. Additionally, the work aims to explore innovative approaches, including nanoparticle-based delivery systems, to enhance the efficacy of miRNA-based therapies. Ultimately, this research aims to provide insights into future directions for precision medicine in TC, bridging the gap between molecular discoveries and clinical applications.

Current Role of MicroRNAs in the Diagnosis and Clinical Management of Germ Cell Tumors

Germ cell tumors (GCTs) are a rare and heterogeneous group of neoplasms arising from primitive germ cells. MicroRNAs are small noncoding RNAs that have emerged as potential cancer biomarkers in the last decade. In particular, miR-371a-3p has shown good diagnostic performance for germ cell neoplasia in situ-derived testicular GCTs in several well-established cohorts and is expected to enter the clinical arena in the near future. GCTs universally exhibit high expression of miR-371-373 and miR-302/367 clusters and low expression of let-7 family miRNAs. Further studies are needed to assess the potential role of these miRNAs as biomarkers of ovarian and extragonadal GCTs.

Insights into the genetic and epigenetic mechanisms governing X-chromosome-linked-miRNAs expression in cancer; a step-toward ncRNA precision

Sex chromosomes play a significant role in establishing sex-specific differences in gene expression, thereby contributing to phenotypic diversity and susceptibility to various diseases. MicroRNAs (miRNAs), which are small non-coding RNAs encoded by both the X and Y chromosomes, exhibit sex-specific regulatory characteristics. Computational analysis has identified several X-linked miRNAs differentially expressed in sex-specific cancers. This review aims to elucidate the genetic and epigenetic mechanisms that govern the sex-specific expression of X- and Y-linked miRNAs, with particular attention to their functional role in regulating diverse cellular processes in different cancer pathways. In addition, this review provides a comprehensive understanding of the targeted therapeutic interventions and critical insights into the potential clinical implications of targeting sex-specific miRNAs. In conclusion, this review opens new horizons for further research to effectively translate these findings into viable treatment options.

Management of Small Testicular Masses: A Delphi Consensus Study

BACKGROUND AND OBJECTIVE

The majority of small testicular masses (STMs) are benign and therefore radical orchidectomy (RO) may represent overtreatment. In appropriately selected patients, surveillance or testis-sparing surgery (TSS) is an alternative option to preserve testicular function. Since there are no clear guidelines, we aimed to develop consensus recommendations on the management of STMs.

METHODS

A four-round Delphi study was conducted by 24 experts representing multiple subspecialties to reach consensus. Consensus was defined as ≥75% of the participants scoring within the same 3-point grouping (1-3, disagree; 4-6, uncertain; 7-9, agree.). The first two rounds were survey based, the third round was an online meeting to discuss uncertainties from the first two rounds, and the fourth round was a review of the final consensus statements from rounds 1-3.

KEY FINDINGS AND LIMITATIONS

The initial survey consisted of 126 statements. Following the four rounds of assessment, a list of 96 statements were produced, which focused on clinical and biochemical assessment, colour Doppler ultrasound (CDUS) characteristics, and management options including surveillance, RO, and TSS. Management should be personalised according to risk factors for testicular cancer, fertility status, uni- or bilateral tumours, status of the contralateral testis, and CDUS characteristics, with solid lesions displaying vascularity and hypoechogenicity being more suspicious for malignancy. The consensus statements are prone to a bias, and some may not reflect robust, randomised evidence.

CONCLUSIONS AND CLINICAL IMPLICATIONS

The expert panel has produced consensus recommendations on the management of STMs, and TSS should be considered in patients with an STM. The recommendations could aid in the dissemination of best practice.

PATIENT SUMMARY

There are no clear guidelines on the management of small testicular masses. Excising the whole testicle (radical orchidectomy) with a small or an indeterminate mass may affect fertility and hormonal function. A panel of experts was formed, and consensus recommendations were developed on how to deal with small and indeterminate testicular masses, which include surveillance or testis-sparing surgery.

Prostate cancer epigenetics - from pathophysiology to clinical application

Prostate cancer is a multifactorial disease influenced by various molecular features. Over the past decades, epigenetics, which is the study of changes in gene expression without altering the DNA sequence, has been recognized as a major driver of this disease. In the past 50 years, advancements in technological tools to characterize the epigenome have highlighted crucial roles of epigenetic mechanisms throughout the entire spectrum of prostate cancer, from initiation to progression, including localized disease, metastatic dissemination, castration resistance and neuroendocrine transdifferentiation. Substantial advances in the understanding of epigenetic mechanisms in the pathophysiology of prostate cancer have been carried out, but translating preclinical achievements into clinical practice remains challenging. Ongoing research and biomarker-oriented clinical trials are expected to increase the likelihood of successfully integrating epigenetics into prostate cancer clinical management.

In silico identification of multidrug resistance gene (MDR)-targeted transposon miRNAs in human cancer

miRNAs are small RNA molecules that regulate gene expression and play important roles in various biological processes in cells. The discovery of miRNAs is also of great importance in cancer research. miRNAs enable the development of new approaches in cancer treatment by regulating gene expression in cancer cells and have an important place in cancer development, treatment, and diagnosis. Multidrug resistance (MDR) in cancer is associated with the overexpression of ATP-binding cassette (ABC) transporter proteins in cancer cells. MDR contributes to the dysregulation of ABC transporter proteins, and miRNAs mediate MDR in various cancers, resulting in drug resistance. In this study, it was aimed to identify new miRNA sequences in genes associated with multidrug resistance in cancer using in silico method. After obtaining the mature human miRNA sequences in the miRBASE database, BLAST analyses were performed with these sequences for five multidrug resistance genes (ABCB1, ABCC3, ABCC10, ABCC11, ABCG2) known to be associated with cancer. The RNAhybrid tool was used to find the minimum free energy hybridization of gene and miRNA. The target genes of pre-miRNAs and the metabolic pathways in which the target genes play a role were identified with GeneMANIA, SRplot, miRTargetLink programs. Phylogenetic trees of miRNAs belonging to genes were created using the MEGA X software. Secondary structures of pre-miRNA sequences were determined using the RNAfold Web Server program. According to the data obtained from the study, 107 miRNAs associated with multidrug resistance were identified in human cancers. Transmembrane transporter, drug transport and response to drug functions, and metabolic activities of miRNA-related pathways of MDR genes in various cancer types were determined. Multidrug resistance (MDR) in cancer is often associated with overexpression of ABC transporter proteins, which can lead to failure of cancer treatments. Additionally, the relationship of miRNAs with ABC transporter proteins constitutes an important research area to understand the mechanisms of drug resistance and develop new treatment strategies.

miR-5100 Overexpression Inhibits Prostate Cancer Progression by Inducing Cell Cycle Arrest and Targeting E2F7

Despite advances in treatment, prostate cancer remains a leading cause of cancer-related deaths among men, highlighting the urgent need for innovative therapeutic strategies. MicroRNAs (miRNAs) have emerged as key regulatory molecules in cancer biology. In this research, we investigated the tumor-suppressive role of miR-5100 in PCa and its underlying molecular mechanism. By using RT-qPCR, we observed lower miR-5100 expression in PCa cell lines than in benign prostate cells. Functional assays demonstrated that miR-5100 overexpression significantly suppressed PCa cell proliferation, migration, and invasion. By using RNA-sequencing, we identified 446 down-regulated and 806 upregulated candidate miR-5100 target genes overrepresenting cell cycle terms. Mechanistically, E2F7 was confirmed as a direct target of miR-5100 using the reporter gene assay and RIP assay. By conducting flow cytometry analysis, cell cycle progression was blocked at the S phase. E2F7 overexpression partially mitigated the suppressive impact of miR-5100 in PCa cells. In conclusion, miR-5100 is a tumor suppressor in PCa by blocking cell cycle and targeting E2F7.

Recent progress in microRNA research for prostate cancer

In recent years, prostate cancer (PCa) has seen an increasing prevalence, particularly among middle-aged and older men, positioning it as a significant health concern. Current PCa screening predominantly utilizes prostate-specific antigen (PSA) testing, digital rectal examination (DRE), and the Gleason scoring system. However, these diagnostic methods can sometimes be imprecise. Research has identified that specific microRNAs (miRNAs) exhibit altered expression levels in PCa patients, suggesting their potential as biomarkers for both diagnosis and prognosis. Furthermore, advancements in integrating miRNAs with traditional Chinese medicine (TCM) have shown promising results in PCa treatment, potentially serving as micro-markers for TCM syndrome differentiation and treatment effectiveness. Recent developments in anti-cancer therapies that target miRNAs have also been implemented in clinical settings, laying the groundwork for personalized and precise treatment strategies for PCa. This review aims to summarize the expression patterns of miRNAs in PCa patients and explore their roles in the diagnosis, treatment, and prognosis of the disease.

Malignant ovarian and testicular germ cell tumors: Common characteristics but different prognoses

Both ovarian and testicular germ cell tumors (GCTs) arise from the primordial germ cell and share many similarities. Both malignancies affect mainly young patients, show remarkable responsiveness to cisplatin-based therapy, and have an excellent prognosis, which also highlights the importance of minimizing long-term side effects. However, certain differences can be noted: The spreading of the disease differs, and the staging system and treatment recommendations are dissimilar. Moreover, the prognosis for ovarian GCTs is significantly inferior to that for testicular cancer, as exemplified in this review comparing the survival in Swedish patients diagnosed with testicular (1995-2022) and ovarian (1990-2018) GCTs. The 5-year overall survival in ovarian GCTs was 85.2%, versus 98.2% for testicular GCTs. How can this be explained? One reason may be the difference in knowledge, experience, and evidence because the incidence rate of testicular cancer is more than 15 times that of ovarian GCTs. Given the rarity of the disease in women and the lack of established guidelines, a comprehensive understanding of the disease and treatment decisions is challenging. The main objective of this review is to derive insights from testicular GCTs (seminoma and non-seminoma) by reviewing etiological, tumor biological, and clinical knowledge, and to thereafter suggest actions for ovarian GCTs based on this. We hypothesize that by adopting specific treatment strategies from testicular GCTs-including de-escalating adjuvant chemotherapy for low-risk patients and implementing more standardized and intensive treatment protocols in cases of relapse-we can improve the prognosis and minimize long-term side effects in ovarian GCT patients.

Analysis of MicroRNA-371-373 supports that a subset of spermatocytic tumors demonstrates biologic features similar to those of GCNIS-derived germ cell tumors

Spermatocytic tumors are rare testicular tumors occurring predominantly in older men. Most show a classical tripartite morphology (different from seminoma) and are benign. However, well-documented cases of malignant spermatocytic tumors exist. Our previous work showed that a subset of spermatocytic tumors exhibiting TP53 mutations, DNA methylation profiles closer to seminomas, and/or gains in chromosome 12p exhibited aggressive characteristics, including sarcomatoid transformation and metastatic dissemination. The microRNA-371-373 cluster is a promising biomarker which is upregulated in non-teratoma germ cell tumors with malignant behavior. In this work we analyze microRNAs-371-373 b y quantitative real-time polymerase chain reaction in 18 spermatocytic tumors representative of the whole clinical spectrum, including 6 with aggressive features (sarcomatoid transformation, metastases, or gains in chromosome 12p). The levels of microRNAs-371-373 were significantly higher in non-teratoma germ cell tumors compared to spermatocytic tumors, overall (p < 0.0001). Importantly, levels of microRNA-371-373 were higher in spermatocytic tumors with aggressive features compared to non-aggressive neoplasms. The highest levels were observed in one tumor showing isochromosome 12p. These results further support our previous findings that a subset of spermatocytic tumors are intermediate between so-called type II and type III germ cell tumors and that embryonic microRNAs play a role in aggressive behavior in spermatocytic tumors. Accordingly, this subset of tumors may behave aggressively and require close follow up. In the future, this opens an opportunity for microRNA testing in serum of spermatocytic tumor patients for risk stratification purposes.

Evolution of Testicular Germ Cell Tumors in the Molecular Era With Histogenetic Implications

The current WHO classification of testicular germ cell tumors is based on the pathogenesis of the tumors driven by different genomic events. The germ cell neoplasia in situ is the precursor lesion for all malignant germ cell tumors. The current understanding of pathogenesis is that the developmental and environmental factors with the erasure of parental genomic imprinting lead to the development of abnormal gonocytes that settle in the "spermatogonial Niche" in seminiferous tubules. The abnormal primordial germ cells in the seminiferous tubules give rise to pre-GCNIS cells under the influence of TPSY and OCT4 genes. The whole genome duplication events give rise to germ cell neoplasia in situ, which further acquires alterations in 12p along with NRAS and KRAS mutations to produce seminoma. A subset of seminomas acquires KIT mutation and does not differentiate further. The remaining KIT-stable seminomas differentiate to nonseminomatous GCTs after obtaining recurrent chromosomal losses, epigenetic modification, and posttranscriptional regulation by multiple genes. Nonseminomatous germ cell tumors also develop directly from differentiated germ cell neoplasia in situ. TP53 pathway with downstream drivers may give rise to somatic-type malignancies of GCT. The GCTs are remarkably sensitive to cisplatin-based combination chemotherapy; however, resistance to cisplatin develops in up to 8% of tumors and appears to be driven by TP53/MDM2 gene mutations. Serum and Plasma miRNAs show promise in diagnosing, managing, and following up on these tumors. The mechanisms underlying the development of most tumors have been elucidated; however, additional studies are required to pinpoint the events directing specific characteristics. Advances in identifying specific molecular markers have been seen recently and may be adopted as gold standards in the future.

MicroRNAs for detecting occult genitourinary cancer

PURPOSE OF REVIEW

Genitourinary (GU) malignancies are a real burden in global health worldwide. Each model has its own clinical challenges, and the early screening and/or detection of occult cancer in follow-up is transversal to all of them. MicroRNAs (miRNAs) have been proposed as minimally invasive liquid biopsy cancer biomarkers, due to their stability and low degradation.

RECENT FINDINGS

The different GU tumor models are in different stages concerning miRNAs as biomarkers for cancer detection. Testicular germ cell tumors (TGCTs) already have a specific defined target, miR-371a-3p, that has shown high sensitivity and specificity in different clinical settings, and is now in final stages of preanalytical testing before entering the clinic. The other GU malignancies are in a different stage, with many liquid biopsy studies (both in urine and plasma/serum) being currently performed, but there is not an agreeable miRNA or set of miRNAs that is ready to follow the footsteps of miR-371a-3p in TGCTs.

SUMMARY

Further studies with proper molecular characterization of miRNA profiles of GU malignancies and standardization of sampling, biobanking and formal analysis may aid in the advance and choosing of specific target sets to be used for occult cancer detection.

Biomarkers for Salvage Therapy in Testicular Germ Cell Tumors

The outcome of metastatic testicular germ cell tumor patients has been dramatically improved by cisplatin-based chemotherapy combinations. However, up to 30% of patients with advanced disease relapse after first-line therapy and require salvage regimens, which include treatments with conventional-dose chemotherapy or high-dose chemotherapy with autologous stem cell transplantation. For these patients, prognosis estimation represents an essential step in the choice of medical treatment but still remains a complex challenge. The available histological, clinical, and biochemical parameters attempt to define the prognosis, but they do not reflect the tumor's molecular and pathological features and do not predict who will exhibit resistance to the several treatments. Molecular selection of patients and validated biomarkers are highly needed in order to improve current risk stratification and identify novel therapeutic approaches for patients with recurrent disease. Biomolecular biomarkers, including microRNAs, gene expression profiles, and immune-related biomarkers are currently under investigation in testicular germ cell tumors and could potentially hold a prominent place in the future treatment selection and prognostication of these tumors. The aim of this review is to summarize current scientific data regarding prognostic and predictive biomarkers for salvage therapy in testicular germ cell tumors.

Integrated Microarray-Based Data Analysis of miRNA Expression Profiles: Identification of Novel Biomarkers of Cisplatin-Resistance in Testicular Germ Cell Tumours

Testicular germ cell tumours (TGCTs) are the most common solid malignancy among young men, and their incidence is still increasing. Despite good curability with cisplatin (CDDP)-based chemotherapy, about 10% of TGCTs are non-responsive and show a chemoresistant phenotype. To further increase TGCT curability, better prediction of risk of relapse and early detection of refractory cases is needed. Therefore, to diagnose this malignancy more precisely, stratify patients more accurately and improve decision-making on treatment modality, new biomarkers are still required. Numerous studies showed association of differential expressions of microRNAs (miRNAs) with cancer. Using microarray analysis followed by RT-qPCR validation, we identified specific miRNA expression patterns that discriminate chemoresistant phenotypes in TGCTs. Comparing CDDP-resistant vs. -sensitive TGCT cell lines, we identified miR-218-5p, miR-31-5p, miR-125b-5p, miR-27b-3p, miR-199a-5p, miR-214-3p, let-7a and miR-517a-3p as significantly up-regulated and miR-374b-5p, miR-378a-3p, miR-20b-5p and miR-30e-3p as significantly down-regulated. In patient tumour samples, we observed the highest median values of relative expression of miR-218-5p, miR-31-5p, miR-375-5p and miR-517a-3p, but also miR-20b-5p and miR-378a-3p, in metastatic tumour samples when compared with primary tumour or control samples. In TGCT patient plasma samples, we detected increased expression of miR-218-5p, miR-31-5p, miR-517a-3p and miR-375-5p when compared to healthy individuals. We propose that miR-218-5p, miR-31-5p, miR-375-5p, miR-517-3p, miR-20b-5p and miR-378a-3p represent a new panel of biomarkers for better prediction of chemoresistance and more aggressive phenotypes potentially underlying metastatic spread in non-seminomatous TGCTs. In addition, we provide predictions of the targets and functional and regulatory networks of selected miRNAs.