Mouse Anti-Human BRAF V600E monoclonal antibody, clone JID711

Metanephric adenoma (MA) is an uncommon benign renal tumor whose histomorphological aspect resembles that of Wilms' tumor and papillary renal cell carcinoma. From a diagnostic and therapeutic perspective, recognition of this entity is important as it has a more favorable clinical outcome compared with Wilms' tumor and papillary renal cell carcinoma. MA should not be treated with nephrectomy if the tumor size is small, opting for a conservative treatment. However, the preoperative diagnosis of this disease is extremely challenging. The present study describes a case of this rare disease, showing an ambiguous radiological imaging and that only after a percutaneous biopsy, was defined as a MA and treated with partial nephrectomy. Moreover, the histological diagnosis of this case was partially complicated by the equivocal immunohistochemical analysis showing negativity for BRAF VE1 staining. Only the mutational analysis demonstrated the presence of the BRAF V600K mutation (for the first time described in a case of metanephric adenoma), highlighting the necessity of sequencing in case of MA with negativity for BRAF VE1 clone.

Detection of BRAF(V600E) within cell free tumor DNA (ctDNA) is emerging as a promising means to improve patients' stratification or enable BRAF inhibitor (BRAFi) therapeutic monitoring in a minimally invasive manner. Here, we investigated whether extracellular vesicle-(EV)-associated-DNA (EV-DNA) has value as an alternative source of circulating BRAF(V600E). To do so, we identified a clinical practice-compatible protocol for the isolation of EV-DNA and assessed BRAF gene status on plasma samples from metastatic melanoma patients at the beginning and during BRAFi therapy. This protocol uses a peptide with high affinity for EVs and it has been found to recover more mutant DNA from plasma than standard ultracentrifugation. Molecular analyses revealed that mutant DNA is largely unprotected from nuclease digestion, interacting with the outer side of the EV membrane or directly with the peptide. When used on clinical samples, we found that the protocol improves the detection of BRAF(V600E) gene copies in comparison to the reference protocol for ctDNA isolation. Taken together, these findings indicate that EVs are a promising source of mutant DNA and should be considered for the development of next-generation liquid biopsy approaches.