VE1 antibody immunoreactivity in normal anterior pituitary and adrenal cortex without detectable BRAF V600E mutations.

OBJECTIVES The VE1 monoclonal antibody was developed to recognize the V600E mutation in BRAF, which is found in various tumors. METHODS We report that the VE1 antibody stains normal anterior pituitary gland and adrenal cortex, which lack detectable BRAF V600E mutations. RESULTS Staining with the VE1 antibody was seen in the adenohypophysis and correlated well with adrenocorticotropic hormone (ACTH)-positive cells. ACTH-positive cells were typically most concentrated in the central mucoid wedge and pars intermedia, and VE1 staining was strong in these regions. Moreover, VE1 staining was seen in ACTH-expressing pituitary adenomas without detectable BRAF mutations. VE1 staining of the adrenal cortex was also significant, with the strongest staining seen in the inner segment of the zona fasciculata. Parathyroid glands, pancreatic islets, or parafollicular C cells in the thyroid showed no VE1 staining. CONCLUSIONS Overall, VE1 staining of endocrine tissues strongly suggests limitations on the use of this antibody for the detection of BRAF mutations.