INSM1 and neuroendocrine neoplasm: An overview of the 2022 WHO Classification of Neuroendocrine Neoplasms stated that CgA, Syn, and insulinoma-associated protein 1 (INSM1) represent general neuroendocrine markers and recommended the simultaneous use of Syn and INSM1, as this combination can reliably identify the neuroendocrine component (both NET and NEC) in nearly all cases.