Wilms tumor in Morocco: Epidemiology, challenges in management, and the promise of microRNAs as diagnosis biomarkers.

e22009 Background: Wilms tumor (WT) or nephroblastoma is the most common pediatric kidney cancer, accounting for 95% of renal tumors in children. Its diagnosis and management can be challenging, with issues such as misdiagnosis, delayed risk stratification and subtyping, and variable responses to preoperative chemotherapy across histotypes. This study presents the epidemiology of WT in Morocco, explores management challenges, and evaluates microRNAs (miRNAs) as potential biomarkers to address these issues. Methods: Clinical data were collected from 84 patients with WT. The clinical and histological profiles were studied, and pre-operative chemotherapy responses were evaluated. Plasma samples were collected from 44 WT patients, 75 healthy controls, 4 patients with other kidney malignancies, and 44 neuroblastoma (NB) patients. The inclusion of non-WT tumors aimed to assess the potential of miRNAs for differential diagnosis. MiRNA expression profiles were assessed using RT-qPCR, with miRNAs selected based on diagnostic accuracy meta-analysis. Results: The median age of WT patients was 36 months, with a female predominance. WT was sporadic in 98% of cases, primarily affecting the left kidney. Stage III and intermediate-risk WT were predominant. Histotype significantly correlated with sex and tumor localization; age correlated with tumor extension, stage, and risk grade. Overall stage correlated with IVC tumor thrombus. During follow-up, 71% achieved remission, 13% died, and 16% relapsed. Tumor response to pre-operative chemotherapy varied across histotype. Regressive, blastemal, and mixed types showed significant volume reduction; epithelial types had moderate response; stromal types responded poorly, with three cases showing volume increase. MiR-130b-3p distinguished WT patients from healthy controls with an AUC of 0.9 but could not differentiate WT from other renal tumors or neuroblastoma. MiR-17-5p had lower diagnostic potential, but combining the two miRNAs increased the AUC to 0.97, supporting the use of miRNA panels for WT diagnosis and stratification. Conclusions: MiR-130b-3p shows promise as a diagnostic biomarker for WT, and its combination with miR-17-5p enhances diagnostic accuracy. However, further analysis should be conducted on a larger cohort of patients. Keywords: Wilms tumor, Epidemiology, Diagnosis, miRNA, Expression profile, RT-qPCR.