Renal pathology in WAGR syndrome

Area of Science:

• Pediatric Oncology
• Developmental Biology
• Molecular Genetics

Background:

• Wilms' tumor (WT) is a pediatric kidney cancer strongly associated with Wilms' tumor-aniridia-genital anomalies-mental retardation (WAGR) syndrome.
• Genetic alterations, particularly deletions in chromosome 11p13, are implicated in WAGR syndrome and WT development.
• Understanding WT pathogenesis is crucial for improving diagnosis and treatment.

Observation:

• A case of a 2-year-old girl with WAGR syndrome and a chromosome 11 deletion presented with Wilms' tumor.
• Pathologic examination revealed findings suggestive of a cystic Wilms' tumor and intralobar nephrogenic rests.
• In-situ hybridization was used to study H19 gene expression in kidney tissue.

Findings:

• H19 gene expression was prominent in the blastemal component of intralobar nephrogenic rests.
• H19 expression decreased with differentiation into tubular structures, mimicking fetal kidney development.
• This pattern contrasts with typical Wilms' tumors where H19 is often not expressed.

Implications:

• The differential diagnosis between hyperplastic nephrogenic rests and early-stage Wilms' tumor is challenging.
• Understanding H19 gene expression patterns may aid in distinguishing benign rests from malignant transformation.
• Further research into molecular events in Wilms' tumor evolution could lead to novel diagnostic markers for paraffin-embedded tissues.