The Spectrum of Neuroendocrine Differentiation Among Gastrointestinal Carcinoids

Abstract Context.—The advent of panneuroendocrine markers has helped to better depict the heterogeneity of gastrointestinal carcinoids. Consequently, it has been proposed that these tumors constitute a histologic spectrum that includes well-, moderately, and poorly differentiated carcinoids. However, the reproducibility of this grading system and its prognostic importance have sometimes been called into question. Objective.—To investigate the potential utility of cell proliferation and oncoprotein markers in augmenting the histologic classification. Design and Setting.—Retrospective study; tertiary care teaching hospital. Methods.—Fifty-eight patients with 41 well-differentiated, 12 moderately differentiated and 5 poorly differentiated carcinoids from various topographic sites of the gastrointestinal tract were selected and immunostained for panneuroendocrine markers, MIB-1, p53, and bcl-2. Main Outcome Measures.—Degree of association between histologic grading, MIB-1, p53, and bcl-2 immunoreactivity and ...