This antibody reacts with a 200kDa protein, identified as heavy subunit of neurofilaments, or NF-H. Neurofilaments make up the main structural elements of axons and dendrites and are found in neurons, peripheral nerves, and sympathetic ganglion cells. Neurofilaments consist of three major subunits with molecular weights of 68kDa (NF-L), 160kDa (NF-M) and 200kDa (NF-H), plus alpha internexin or peripherin. Each neurofilament subunit contains a globular head, an alpha helical rod domain, and variable tail domains that differ in length and amino acid content.

Neurofilament antibody stains a number of neural, neuroendocrine, and endocrine tumors. Neuromas, ganglioneuromas, gangliogliomas, ganglioneuroblastomas, and neuroblastomas stain positively for neurofilament antibody. Neurofilaments are also present in paragangliomas as well as adrenal and extra-adrenal pheochromocytomas. Carcinoids, neuroendocrine carcinomas of the skin, and cell carcinomas of the lung also express neurofilament.