Distinct clinicopathological features in metanephric adenoma harboring BRAF mutation

Area of Science:

• Oncology
• Genetics
• Pathology

Background:

• Metanephric adenoma is a rare renal neoplasm.
• BRAF mutations have recently been identified in metanephric adenoma.
• Understanding BRAF mutation's clinical and morphological impact is crucial.

Purpose of the Study:

• To investigate clinical and morphologic features of BRAF-mutated metanephric adenomas.
• To correlate BRAF mutation status with BRAF V600E immunohistochemical staining.
• To differentiate metanephric adenoma from epithelial-predominant nephroblastomas based on BRAF status.

Main Methods:

• Analysis of 48 metanephric adenomas and 15 epithelial-predominant nephroblastomas.
• BRAF mutation analysis using the BRAF RGQ PCR kit.
• Immunohistochemistry for p16INK4 and VE1 (BRAF V600E specific).

Main Results:

• 85% of metanephric adenomas harbored BRAF V600E mutation; other variants were absent.
• VE1 immunostaining showed 80% sensitivity and 100% specificity for BRAF V600E.
• BRAF V600E mutation correlated with older patients, female predominance, and acinar architecture.
• Epithelial-predominant nephroblastomas were BRAF-wild-type and VE1-negative.

Conclusions:

• BRAF V600E is a frequent driver mutation in metanephric adenoma.
• BRAF V600E-mutated tumors exhibit specific clinical and morphologic characteristics.
• VE1 immunostaining is a useful but not fully sensitive marker for BRAF V600E in metanephric adenoma.