title: Algorithmic approach to neuroendocrine tumors in targeted biopsies: Practical applications of immunohistochemical markers.
abstract: Neuroendocrine tumors (NETs) constitute a heterogeneous group of neoplasms with distinct biological behaviors, depending on the site of origin and the degree of tumor proliferation. Although advances in biochemical and radiological modalities have enhanced the ability to detect NETs, tissue diagnosis remains the gold standard to assess tumor characteristics for treatment decision making. In an era with growing demands for precision diagnostics based on smaller tissue samples, immunohistochemistry has become an indispensable tool in the pathologist's repertoire. In conjunction with clinical findings and cytomorphology, complementary use of 1) markers of neuroendocrine differentiation, 2) markers confirming epithelial nature, 3) markers of cellular proliferation, 4) transcription factors and hormonal markers, as well as 5) predictive and prognostic markers may be necessary to guide patient management in NETs. The current review summarizes common applications of these immunohistochemical markers when confronted with a potential neuroendocrine neoplasm, and proposes a stepwise algorithmic approach to avoid diagnostic errors in targeted biopsies. Cancer Cytopathol 2016;124:871-884. © 2016 American Cancer Society.
authors.affiliation: Department of Pathology, University Health Network, Toronto, Ontario, Canada.|Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Kai
authors.initials: K
authors.lastname: Duan
authors.affiliation: Department of Pathology, University Health Network, Toronto, Ontario, Canada.|Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.|Endocrine Oncology Site Group, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
authors.forename: Ozgur
authors.initials: O
authors.lastname: Mete
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000378:metabolism*; D049109:Cell Proliferation; D006801:Humans; D018358:Neuroendocrine Tumors / Q000378:metabolism / Q000473:pathology*; D057285:Precision Medicine; D011379:Prognosis; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor
keywords: biomarkers; hormones; immunohistochemistry; neuroendocrine tumor; paraganglioma; poorly differentiated neuroendocrine carcinoma; transcription factors