Point of care assessment of melanoma tumor signaling and metastatic burden from µNMR analysis of tumor fine needle aspirates and peripheral blood.

This study evaluates µNMR technology for molecular profiling of tumor fine needle aspirates and peripheral blood of melanoma patients. In vitro assessment of melanocyte (MART-1, HMB45) and MAP kinase signaling (pERK, pS6K) molecule expression was performed in human cell lines, while clinical validation was performed in an IRB-approved study of melanoma patients undergoing biopsy and blood sampling. Tumor FNA and blood specimens were compared with BRAF genetic analysis and cross-sectional imaging. µNMR in vitro analysis showed increased expression of melanocyte markers in melanoma cells as well as increased expression of phosphorylated MAP kinase targets in BRAF-mutant melanoma cells. Melanoma patient FNA samples showed increased pERK and pS6K levels in BRAF mutant compared with BRAF WT melanomas, with µNMR blood circulating tumor cell level increased with higher metastatic burden visible on imaging. These results indicate that µNMR technology provides minimally invasive point-of-care evaluation of tumor signaling and metastatic burden in melanoma patients.

Why and how immunohistochemistry should now be used to screen for the BRAFV600E status in metastatic melanoma? The experience of a single institution (LCEP, Nice, France).

BACKGROUND: Knowledge of the BRAFV600E status is mandatory in metastatic melanoma patients (MMP). Molecular biology is currently the gold standard method for status assessment. OBJECTIVES: We assessed and compared the specificity, sensibility, cost-effectiveness and turnaround time (TAT) of immunohistochemistry (IHC) and molecular biology for detection of the BRAFV600E mutation in 188 MMP. METHODS: IHC, with the VE1 antibody, and pyrosequencing analysis were performed with formalin fixed paraffin embedded tumour samples. RESULTS: The BRAFV600E mutation was detected by pyrosequencing in 91/188 (48%) patients. IHC was strongly positive (3+) in all of these 91 cases. IHC was strongly positive in 9/188 (5%) cases in which the molecular testing failed due to non-amplifiable DNA. Weak or moderate staining was noted in 10/188 (5%) cases in which the molecular biology identified BRAF wild-type tumours. The ratio of the global cost for IHC/molecular biology testing was 1 : 2.2. The average TAT was 48 h vs. 96 h, for IHC vs. molecular biology testing, respectively. CONCLUSIONS: This study showed that VE1 IHC should be a substitute for molecular biology in the initial assessment of the BRAFV600E status in MPP. This methodology needs to be set up in pathology laboratories in accordance with quality control/quality assurance accreditation procedures. Under these strict conditions the question is to know if BRAFV600E-IHC can serve not only as a prescreening tool, but also as a stand-alone test (at least in cases displaying an unequivocally staining pattern) as well as an alternative predictive test for samples for which the molecular biology failed.