Frequent BRAF V600E and TERT promoter-mutated renal epithelial-predominant Wilms tumours with metanephric features: a distinct subset within the Wilms tumour spectrum?

Abstract

Aims: The molecular characteristics and intricate relationships between tumours exhibiting overlapping features of metanephric adenoma (MA) and epithelial Wilms tumour (WT), as well as their pure forms, remain largely enigmatic.

Methods and results: Herein, we conducted a comprehensive genetic analysis of nine epithelial-predominant Wilms tumours, focusing on genetic alterations through expanded targeted sequencing and RNA sequencing (RNA-seq) methodologies. The patients ranged in age from 13 to 61 years, with a mean and median age of 43 and 48 years, respectively. The cohort included seven males and two females. These tumours exhibited immune reactivity for BRAF, WT1, and CD57, and harboured frequent TERT promoter mutations (7/9) and BRAF V600E mutations (8/9). RNA sequencing-based clustering revealed a close similarity between the tumours and MAs, suggesting that they may represent a distinct subset within the Wilms tumour spectrum. Two patients were lost to follow-up, while the remaining seven (7/7) were alive without tumour recurrences or metastases at the time of analysis, with a mean follow-up duration of 78.1 months.

Conclusions: Our research supports the notion previously described that epithelial-predominant Wilms tumours, characterized by frequent TERT promoter and BRAF V600E mutations, represent a distinct subset within the Wilms tumour spectrum. These tumours display an expression profile closely resembling that of metanephric adenomas and are associated with a favourable prognosis.