INSM1, a Novel Biomarker for Detection of Neuroendocrine Neoplasms: Cytopathologists' View

Background: Insulinoma-associated protein 1 (INSM1) has been considered as a novel immunostain for neuroendocrine tumors (NETs) and is hypothesized to be more reliable than first-generation NET biomarkers, such as CGA (chromogranin A), SYP (synaptophysin) and CD56 (neural cell adhesion molecule). In this review, we summarize existing literature on INSM1 ' s reliability as an immunostain for detection of various NETs, its results in comparison to first-generation NET biomarkers, and its expression in both non-NETs and benign tissues/cells on cytology specimens (cell blocks/smears).

Automated summary

INSM1 is considered a reliable immunostain for neuroendocrine tumors compared to first-generation NET biomarkers. Research summarized its performance in detecting various types of NETs, comparing results with other biomarkers, and its expression in non-NETs and benign tissues/cells.