BRAF Exon 15 Mutations in Pediatric Renal Stromal Tumors: Prevalence in Metanephric Stromal Tumors.

BRAF Exon 15 Mutations in Pediatric Renal Stromal Tumors: Prevalence in Metanephric Stromal Tumors.

Hum Pathol. 2016 Oct 18;:

Authors: Marsden L, Jennings LJ, Gadd S, Yu M, Perlman EJ, Cajaiba MM

Abstract
Metanephric stromal tumors are rare renal stromal tumors that predominantly affect children. They belong to the metanephric family of tumors along with metanephric adenofibroma and metanephric adenoma. The previous documentation of BRAF exon 15 mutations in 88% of metanephric adenomas and in isolated cases of metanephric adenofibroma prompted us to investigate the prevalence of these mutations in metanephric stromal tumors and in other pediatric renal stromal tumors. In this study, 17 metanephric stromal tumors, 22 congenital mesoblastic nephromas and 6 ossifying renal tumors of infancy were selected for BRAF exon 15 testing. Tumor genomic DNA was extracted from formalin-fixed paraffin-embedded tissue, followed by PCR amplification and Sanger dideoxy sequencing with primers flanking the BRAF exon 15 gene. BRAF exon 15 mutations were found in 11/17 cases (65%) of metanephric stromal tumors, all corresponding to a thymidine to adenine substitution at codon 600 (BRAF V600E). All other renal stromal tumors tested were negative for BRAF exon 15 mutations. In conclusion, BRAF V600E mutations are encountered in the majority of metanephric stromal tumors, supporting a link with other metanephric tumors and suggesting a clonal event possibly affecting primordial renal cells. In addition, BRAF V600E mutations have been associated with oncogene-induced senescence in other benign tumors, providing clues to the pathogenesis of these neoplasms in keeping with their overall benign behavior. Our results also suggest a potential diagnostic use for BRAF exon 15 mutations in differentiating metanephric stromal tumors from other pediatric renal stromal tumors, particularly in limited samples.

PMID: 27769870 [PubMed - as supplied by publisher]

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