E Haneke1, H J Schulze, G Mahrle. 1. Department of Dermatology, Ferdinand-Sauerbruch-Klinikum, Wuppertal, Germany.
Abstract
BACKGROUND: Chromogranin A (CGA) is the major protein of neurosecretory granules (NSG) of cells of the diffuse neuroendocrine system, and the amount of CGA corresponds to the number of NSGs. OBJECTIVE: Because formalin fixation may destroy NSGs, a study was performed to examine the presence of CGA in Merkel cell carcinoma (MCC) to determine whether CGA depends on the presence of intact NSGs. METHODS: Formalin-fixed, paraffin-embedded tissue of 15 MCCs was investigated by immunohistochemistry and immunoelectron microscopy for the presence of CGA and NSGs. RESULTS: CGA was demonstrated in 12 of 15 MCCs by immunochemistry and in 6 of 10 MCCs by immunoelectron microscopy although intact NSGs could not be discerned in all cases. CONCLUSION: CGA remains demonstrable even when no morphologically intact NSGs are present, which suggests that CGA is not exclusively responsible for the electron density of NSGs.
BACKGROUND:Chromogranin A (CGA) is the major protein of neurosecretory granules (NSG) of cells of the diffuse neuroendocrine system, and the amount of CGA corresponds to the number of NSGs. OBJECTIVE: Because formalin fixation may destroy NSGs, a study was performed to examine the presence of CGA in Merkel cell carcinoma (MCC) to determine whether CGA depends on the presence of intact NSGs. METHODS:Formalin-fixed, paraffin-embedded tissue of 15 MCCs was investigated by immunohistochemistry and immunoelectron microscopy for the presence of CGA and NSGs. RESULTS:CGA was demonstrated in 12 of 15 MCCs by immunochemistry and in 6 of 10 MCCs by immunoelectron microscopy although intact NSGs could not be discerned in all cases. CONCLUSION:CGA remains demonstrable even when no morphologically intact NSGs are present, which suggests that CGA is not exclusively responsible for the electron density of NSGs.