Spectrum of PTEN Expression in Non-Pancreatic Gastrointestinal Neuroendocrine Tumors
Maryam J Zenali, Russell Broaddus, Ronald Bassett, Stanley R Hamilton. The University of Texas MD-Anderson Cancer Center, Houston, TX; The University of Texas MD Anderson Cancer Center, Houston, TX
Background: Loss of PTEN expression is associated with tumorigenesis in several tumor types including endometrial, prostatic and colorectal adenocarcinoma. PTEN expression profile in non-pancreatic gastrointestinal neuroendocrine tumors is unclear. In this study, we evaluated PTEN immunoreactivity in 104 neuroendocrine tumors of the foregut, midgut, and hindgut.
Design: 119 cases of non-pancreatic gastrointestinal neuroendocrine tumors were collected from the pathology archives, 2002 to 2011. Sufficient material was available in104 cases. In 37 cases both primary and metastasis and in 4 more than one primary or metastatic site were examined. Immunohistochemistry for PTEN (Dako; clone: 6H2.1; dilution 1:100) was performed and recorded as P: strong homogenous; R: reduced in more than 50%; H: heterogeneous: positive with few foci of loss; L: loss in all or in overwhelming majority.
Results: From 104 cases, 98 were low grade, 4 intermediate, and 2 high grade. Locations were ileum (74), stomach (12), colorectal (11), duodenum (4), jejunum (2), and esophagus (1). Majority were high stage (III+IV: 86/104) and 82 of 104 had positive lymph nodes. Immunohistochemical results are summarized in tables 1 and 2.
|Patterns of Staining||Loss||Heterogeneous||Reduced||Positive|