Pancreatic endocrine tumors-c-erb B2 (Her-2/neu), bcl-2, and p-53 immunohistochemical testing and their value in assessing prognosis.
BACKGROUND
In an attempt to identify better prognostic factors, and the genetic basis of pancreatic endocrine tumors (PETs), we evaluated immunohistochemical reactivity for c-erb B2 (Her-2/neu), bcl-2, and p53.


METHODS
Two pathologists reviewed hematoxylin and eosin slides and immunohistochemical stains from 28 cases, 27 tumors and 1 nesidioblastosis. Using WHO criteria for malignancy (presence of local or lymphovascular invasion and/or metastases), cases were divided into malignant (20 cases) and benign or uncertain (8 cases). Nuclear staining in >1% of cells was considered positive for p53 and bcl-2, whereas membranous staining was considered positive for c-erb B2 (Her-2/neu).


RESULTS
All cases were nonimmunoreactive with anti-c-erb B2 (Her-2/neu), but focal granular or diffuse cytoplasmic staining was seen in occasional neoplasms. One malignant PET showed reactivity with anti-p53, whereas all others were negative. bcl-2 reactivity was identified in 15/28 cases: 9/20 malignant PETs and 6/8 others were positive.


CONCLUSIONS
c-erb B2 (Her-2/neu) and p53 are not useful prognostic factors in PET. c-erb B2 (Her-2/neu) staining must be carefully evaluated to avoid the misinterpretation of artifactual/background staining. bcl-2 is occasionally expressed in PET, but the significance of this finding is still to be determined.
Proca
Daniela M
DM
Department of Pathology, The Ohio State University, Marysville, OH 43040, USA. proca-1@medctr.osu.edu.
Frankel
Wendy L
WL
D006801:Humans; D010179:Pancreas / Q000737:chemistry / Q000166:cytology; D010190:Pancreatic Neoplasms / Q000737:chemistry*; D011379:Prognosis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*
D019253:Proto-Oncogene Proteins c-bcl-2; D018719:Erb-b2 Receptor Tyrosine Kinases; D016159:Tumor Suppressor Protein p53