Wilms' tumor (WT), sometimes referred to as nephroblastoma, is a cancerous kidney tumor that makes up 5% of pediatric malignancies and 95% of malignant kidney tumors in childhood [1]. It occurs in around 1 in every 10,000 children [2]. The syndrome arises from atypical kidney formation during the embryonic phase, particularly at the mesenchymal-epithelial transition (MET) that occurs at the beginning of nephrogenesis [3]. It commonly impacts children between the ages of 0 and 4, with most diagnoses occurring between the ages of 3 and 4 and it affects both men and girls equally [1].

While the majority of WT cases are unilateral, occurring in only one kidney, approximately 5–10% of tumors involve both kidneys simultaneously [4], [5]. The majority of WT cases, around 98–99%, occur sporadically, whereas a small percentage, about 1–2%, are familial [6]. Metastatic forms are seen in around 12% of cases [7], with the majority (80%) affecting the lungs and a smaller proportion (10%) affecting the liver [8]. However, in rare instances, metastasis to the lymph nodes or bones may be found [6]. Approximately 20% of WTs are incidentally detected during normal check-up visits, as tumors can grow to a significant size without showing any specific symptoms [9]. Nevertheless, WT is typically distinguished by the formation of a tangible rigid mass or enlargement in the abdomen, which may be accompanied by abdominal discomfort, internal bleeding inside the tumor, presence of blood in urine under microscopic examination, high blood pressure, fever, and vomiting [10]. Imaging, particularly ultrasound, aids in establishing the diagnosis, which can reveal the location of the mass within or outside the kidney, as well as its composition (solid or cystic). Subsequently, three-dimensional imaging techniques such as MRI scan or CT are conducted, which are necessary for determining the extent of the disease and for initial monitoring of the condition [11].

WT originates from remaining blastema cells in the kidney, referred to as nephrogenic rests, believed to constitute early stages of the tumor [12]. Tumors can form in nephrogenic rests, with bilateral Wilms tumors being more prevalent in girls and linked to specific congenital disorders like as aniridia and hemihypertrophy. The fetal kidney is formed from the ureteric bud and metanephric mesenchyme, while Wilms tumors arise from the aberrant presence of nephrogenic cells [12].

WT is managed according to either the NWTS North American protocol or the SIOP European protocol [4], [13]. In Morocco and many parts of Europe, the SIOP procedure is utilized, involving the administration of chemotherapy before surgery, followed by the complete removal of the kidney along with the tying off of the blood vessels and the removal of the lower part of the ureter. This is then followed by postoperative chemotherapy, typically using a combination of drugs. In certain cases, post-operative radiation therapy may be administered alongside chemotherapy, depending on the histology and stage of the tumor [14]. However, despite their effectiveness in increasing survival rates, these treatments can also cause negative side effects. These side effects include short-term toxicity, especially affecting the GIT and cardiac systems, as well as long-term toxicity. Chronic poisoning may cause hindered growth of bones, which could result in scoliosis and an increased likelihood of acquiring secondary cancers [6].

MicroRNAs (miRNAs) are small, conserved, non-coding RNA molecules that consist of a single strand and are typically 20–22 nucleotides long [15], [16]. Their primary roles involve regulating target mRNAs post-transcriptionally by either inhibiting translation or promoting mRNA degradation [17], [18]. MiRNAs were initially discovered as regulators of proliferation, apoptosis, and cellular differentiation [19]. The dysregulation of specific miRNAs (referred to as "oncomiR") has been linked to the formation of particular cancers [20]. Multiple studies have documented the abnormal regulation of miRNAs in different tumors, including urothelial, and gastric cancer and modified expression of these miRNAs has been suggested as a means of diagnosing and predicting the outcome of these diseases [21], [22]. The genesis of WT involves the dysregulation of epithelial-mesenchymal transition (EMT), cell migration, invasion, cell proliferation, and metastasis. This study focuses on the investigation of the functions of different cancer-causing and tumor-suppressing miRNAs in WT, aiming to enhance our comprehension of the molecular mechanisms involved in the initiation and advancement of WT. We also explore the biological importance and medical application of miRNAs in the prognosis and diagnosis of WT.

A review was conducted by searching the online medical databases PUBMED and NCBI for certain phrases. Research on "miRNA," "nephroblastoma," "carcinogenesis," "pathogenesis," and "Wilms' tumors" was finished by December 29, 2023. To provide a comprehensive overview of the role of miRNAs in Wilms' tumor development and pathogenesis, priority was given to papers with robust experimental methodologies such as clinical guidelines, meta-analyses, randomized clinical studies, systematic reviews, original papers, and narrative reviews.