For example, nuclear overexpression of the protein arginine methyltransferase-5 (PRMT5), which is a chromatin-modifying enzyme, was reported to be more frequent in pulmonary carcinoids than in neuroendocrine carcinomas, suggesting different epigenetic regulatory mechanisms controlling oncogenesis in carcinoids as compared with high-grade pulmonary neuroendocrine neoplasms [56]. Here, PRMT5 is linked to neuroendocrine carcinoma.