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

@entity1 @entity5 @entity406 @entity817 @entity320
BACKGROUND: Knowledge of the BRAFV600E status is mandatory in @entity320 @entity1 (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 @entity406 fixed @entity5 samples. RESULTS: The BRAFV600E mutation was detected by pyrosequencing in 91/188 (48%) @entity1 . 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 @entity817 wild-type @entity5 . 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.
