title: HER-2/neu expression in pancreatic adenocarcinoma: relation to tumor differentiation and survival.
abstract: HER-2/neu expression in pancreatic adenocarcinoma has been inconsistently reported and has not been fully evaluated with respect to histologic grade and tumor grade heterogeneity. We studied HER-2/neu expression in a series of 79 primary pancreatic carcinomas using immunohistochemical methods, with expression scored for each histologic grade represented in each tumor. We found significantly lower expression of HER-2/neu in poorly differentiated (PD) portions of tumors-those areas lacking glandular differentiation-compared to well-differentiated (WD) and moderately differentiated (MD) portions of tumors. Forty-two of 68 (62%) invasive tumors with WD or MD glands showed moderate or strong expression of HER-2/neu in WD/MD areas; only 6 of 32 (19%) invasive tumors with PD areas showed similar expression in PD. In mutually exclusive patient sets, we also found a statistically different prevalence of HER-2/neu expression in patients with PD (6/32 cases; 19%) and without PD (29/47 cases; 62%) tumors (p < 0.001). Twenty-three cases had directly comparable areas of PD versus MD or WD. In 19 of 23 cases HER-2/neu expression was graded comparatively lower (or negative) in areas of PD than in MD or WD. Overall 46 of 79 cases (58%) showed moderate to strong HER-2/neu expression inclusive of all histologic grades, and 63 of 79 (80%) cases were HER-2/neu positive, if including weak or focal staining. There was no significant difference in the survival of patients with HER-2/neu-positive versus-negative tumors or in patients with versus without PD tumors. We have confirmed that although HER-2/neu gene expression is common to many pancreatic carcinomas, it is not common to tumors lacking glandular differentiation. HER-2/neu gene expression could not be related to survival differences--perhaps due to overall poor survival within adenocarcinomas of the pancreas--but the pattern of HER-2/neu expression suggests a relationship to glandular differentiation and early oncogenesis.
authors.affiliation: Department of Pathology, Wayne State University School of Medicine, Harper Hospital, Detroit, Michigan, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Dugan
authors.forename: S T
authors.initials: ST
authors.lastname: Dergham
authors.forename: R
authors.initials: R
authors.lastname: Kucway
authors.forename: K
authors.initials: K
authors.lastname: Singh
authors.forename: L
authors.initials: L
authors.lastname: Biernat
authors.forename: W
authors.initials: W
authors.lastname: Du
authors.forename: V K
authors.initials: VK
authors.lastname: Vaitkevicius
authors.forename: J D
authors.initials: JD
authors.lastname: Crissman
authors.forename: F H
authors.initials: FH
authors.lastname: Sarkar
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D015870:Gene Expression; D018734:Genes, erbB-2; D006801:Humans; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D016019:Survival Analysis