IFN-alpha receptor mRNA expression in a United States sample with predominantly genotype 1a/I chronic hepatitis C liver biopsies correlates with response to IFN therapy.

Our aim was to assess whether, in the United States, with the predominant hepatitis C viral (HCV) genotypes 1a/I and 1b/II, hepatic interferon-alpha receptor (IFNAR) mRNA expression correlated with response to IFN therapy, levels of HCV RNA, or histologic activity index (HAI). Nine of 24 patients (38%) had an initial response to IFN treatment, 5 of whom (21%) had a sustained response. The corrected hepatic IFNAR mRNA expression (measured by RT-PCR) for the sustained responder group (mean +/- SE, 0.16 +/- 0.06, n = 5) was significantly higher than for the nonresponding group (0.059 +/- 0.01, n = 15) (p < 0.02). Patients who relapsed had an intermediate value (0.092 +/- 0.029, n = 4). Higher IFNAR expression was inversely correlated with a lower serum HCV RNA titer (p < 0.01), and responders to IFN treatment tended to have a lower titer of HCV RNA (p = 0.056). We found no significant correlation between the amounts of IFNAR with (1) the total HAI (low HAI < or = 7, IFNAR 0.076 +/- 0.013, n = 10; high HAI > or = 8, IFNAR 0.092 +/- 0.027, n = 14, ns) or (2) individual inflammation, necrosis, or fibrosis components of the HAI. As with Japanese HCV patients with genotypes 1b/II-2b/IV, higher hepatic IFNAR mRNA expression in the United States with predominant genotypes 1a/I and 1b/II appears to correlate with response to IFN therapy and a low HCV RNA titer but not with the total HAI or its components.

Multiscreen serum analysis of highly sensitized renal dialysis patients for antibodies toward public and private class I HLA determinants. Implications for computer-predicted acceptable and unacceptable donor mismatches in kidney transplantation.

A multiscreen serum analysis program has been developed that permits a determination of antibody specificity for the vast majority of highly sensitized patients awaiting transplantation. This program is based on a 2 x 2 table analysis of correlations between serum reactivity with an HLA-typed cell panel and incorporates two modifications. One implements the concept of public HLA determinants based on the serologic crossreactivity among class I HLA antigens. The other modification derives from the premise that most highly sensitized patients maintain the same PRA and antibody profiles over many months and even years. Monthly screening results for patients with persistent PRA values can therefore be combined for analysis. For 132 of 150 highly sensitized patients with greater than 50% PRA, this multiscreen serum analysis program yielded information about antibody specificity toward public and private class I HLA determinants. The vast majority of patients (108 of 112) with PRA values between 50 and 89% showed antibody specificity generally toward one, two, or three public markers and/or the more common private HLA-A,B antigens. For 24 of 38 patients with greater than 90% PRA, it was possible to define one or few HLA-specific antibodies. The primary objective of the multiscreen program was to develop an algorithm about computer-predicted acceptable and unacceptable donor HLA-A,B antigens for patients with preformed antibodies. A retrospective analysis of kidney transplants into 89 highly sensitized patients has demonstrated that allografts with unacceptable HLA-A,B mismatches had significantly lower actuarial survival rates than those with acceptable mismatches (P = 0.01). This was shown for both groups of 32 primary transplants (44% vs. 67% after 1 year) and 60 retransplants (50% vs. 68%). Also, serum creatinine levels were significantly higher in patients with unacceptable class I mismatches (3.0 vs. 8.4 mg% [P = 0.007] after 2 weeks; 3.9 vs. 9.1 mg% [P = 0.014] after 4 weeks). Histopathologic analysis of allograft tissue specimens from 47 transplant recipients revealed a significantly higher incidence of humoral rejection (P = 0.02), but not cellular rejection, in the unacceptable mismatch group. These results suggest that the multiscreen program can establish which donor HLA-A,B mismatches must be avoided in kidney transplantation for most highly sensitized patients. For 18 of 150 high PRA renal dialysis patients, the multiscreen program could not define HLA-specific antibody. Most patients had greater than 90% PRA, and many of their sera appeared to contain IgM type nonspecific lymphocytotoxins that could be inactivated by dithioerythreitol (DTE).(ABSTRACT TRUNCATED AT 400 WORDS)

The value of intravenous heme-albumin and plasmapheresis in reducing postoperative complications of orthotopic liver transplantation for erythropoietic protoporphyria.

Erythropoietic protoporphyria (EPP) is marked by a deficiency of ferrochelatase, which occurs in all cells and tissues, preventing effective conversion of proto porphyrin IX to heme and thereby blocking effective feedback inhibition of heme synthesis. The major source of the excess protoporphyrin is the bone marrow. Protoporphyrin IX may accumulate, with resultant toxicity chiefly of the marrow, skin, nervous system, and liver. Orthotopic liver transplantation (OLT) is, at present, the only adequate intervention for severe liver compromise secondary to protoporphyrin deposition, but it has been complicated by severe photosensitivity and polyneuropathy. Intravenous heme and plasmapheresis have been proposed but not previously reported as means to reduce the protoporphyrin burden before liver transplantation. We report a man with EPP who underwent preoperative heme-albumin administration and plasmaphereses that led to marked reductions in plasma and erythrocyte protoporphyrin levels. His OLT was uneventful, and he developed neither polyneuropathy nor exacerbation of photosensitivity.

Vascular endothelial growth factor/vascular permeability factor mRNA expression in patients with chronic hepatitis C and hepatocellular carcinoma.

Angiogenic factors such as vascular endothelial growth factor (VEGF) may be involved in neovascularization of malignant tumors. Our aim was to determine whether there is an increased VEGF mRNA expression in liver from patients with HCC and premalignant hepatitis C virus (HCV) with differing severity of inflammation. VEGF mRNA (VEGF165, VEGF189) was detected by reverse transcription and semi-quantitative polymerase chain reaction (RT-PCR) amplification in all liver samples. There was no difference in VEGF mRNA expression ratios (corrected for glyceraldehyde-3-phosphate dehydrogenase) among three groups: steatohepatitis, as a non-malignant non-viral control, 1. 05+/-0.35, n=8; chronic hepatitis C, 0.86+/-0.27, n=18; hepatocellular carcinoma, 1.06+/-0.43, n=10. VEGF mRNA expression was independent of the severity of HCV inflammation estimated by the histological activity index: low HAI (/=10, n=10), 0.93+/-0.31 vs. 0.81+/-0.24, p=ns. There was no significant difference in mean VEGF expression between HCC tumor (1.06+/- 0.43) and adjacent tissue (0. 85+/-0.42) although the tumors tended to have higher expression than adjacent non-malignant tissues. In conclusion, all liver samples of steatohepatitis, chronic HCV infection and HCC expressed VEGF mRNA, VEGF mRNA may be uniformly expressed in liver tissue, the level of expression is probably not related to virus infection or the severity of inflammation. Other angiogenic or angiostatic factors might be more involved in angiogenesis in HCC.

CXCR4 mRNA expression in colon, esophageal and gastric cancers and hepatitis C infected liver.

We have recently demonstrated by Northern blot and RT-PCR that the mRNA expression of the alpha-chemokine hIRH/SDF-1alpha is reduced in hepatocellular carcinoma (HCC), several digestive tract cancers and premalignant colon adenomas, and that its receptor CXCR4 mRNA expression is reduced in HCC. Here we investigate the expression of CXCR4 mRNA expression in several digestive tract cancers and hepatitis C viral (HCV) infected liver, a premalignant condition. There was no difference in the CXCR4 mRNA expression in colon, esophageal or gastric cancers compared to non-cancerous tissues. This is significantly different from the reduced expression we have seen with hepatocellular carcinoma (p<0.05). To better refine regional tumor or hepatic cytokine mRNA analysis within a biopsy sample we describe a micro-isolation technique for RNA extraction from portal and triad areas of liver biopsies or other small malignant or non-malignant biopsy samples suitable for use in RT-PCR and differential display reactions. In HCV liver biopsies, the expression of hIRH and its receptor CXCR4 mRNA, corrected for G3PDH, was not significantly different from that of control non-HCV (steatosis) biopsies. CXCR4 is expressed on leukocytes and its expression was predicted to correlate with hepatic inflammation. CXCR4 receptor mRNA expression did correlate significantly with that of its ligand hIRH/SDF-1alpha (p=0.001), and with the severity of fibrosis (p<0.05), but not with portal inflammation (p<0.10), piecemeal necrosis (p<0.10), lobular inflammation (p>0.10), the presence of lymphoid aggregates (p>0.10), or the total histological activity index (p=0.07). There was no difference in expression of hIRH or CXCR4 between responders and non-responders to interferon (IFN) treatment, while as a control, the responder group of patients did show a higher expression of IFNalpha receptor than the non-responder group (p=0.05).

Quantitative DNA analysis of small renal cortical neoplasms.

DNA aneuploidy is common in large renal cortical neoplasms (RCNs), but the incidence in small RCNs is not known. This study was undertaken to investigate whether the traditional 3.0-cm size distinction between small (benign) and large (malignant) tumors might have an objective correlate in the form of abnormal DNA content. Quantitative DNA analysis was performed retrospectively, by image analysis, on 59 RCNs measuring 5.0 cm or less from 30 nephrectomy specimens with solitary tumors and 17 with multiple tumors. DNA indices and the proportion of cells with DNA content greater than that of the G0/G1 population were evaluated with respect to tumor size, stage, and histologic parameters. There was a relationship between the presence of detectable nondiploid stem lines (NDSLs) and tumor size, stage, nuclear grade, and proportion of non-G0/G1 cells, but not histologic pattern. The relationship of NDSLs to tumor size was more apparent in the solitary tumor group, while the relationship of a high proportion of non-G0/G1 cells to tumor size was stronger in the multiple tumor group. Our results show that the incidence of NDSLs increases with tumor size and nuclear grade, and suggest that as RCNs enlarge, the emergence of NDSLs heralds potential biologic aggressiveness. Further, solitary tumors and multiple synchronous tumors may be biologically different in terms of etiologic factors and growth potential.

Tumor angiogenesis in stage II colorectal carcinoma: association with survival.

We studied the frequency of microvessels in T3 N0 M0 colorectal carcinomas from patients with widely different survival times. Microvessels (<50 microm diameter) were enhanced by immunostaining with antibody to factor VIII-related antigen and counted in 40x high-power fields in sections of resected carcinomas from 9 patients who died of disease in 24 months or less (short-term survivors) and 13 who had no evidence of disease at 109 months or longer (long-term survivors). The means of the 10 highest counts for each case were compared between the long- and short-term survivor groups. The mean +/- SD microvessel count was 25.4 +/- 6.5 for the short-term survivors and 30.3 +/- 6.4 for the long-term survivors. Median counts were 27.2 and 29.4, respectively. The distribution of microvessel counts was skewed toward higher counts in the long-term survivors. There was no correlation between microvessel counts and tumor site, size, or grade; lymphovascular invasion; or the presence of a mucinous component. Although there was a trend toward a higher frequency of microvessels in patients with longer survival, it is unlikely that microvessel count is an independent prognostic indicator for patients with T3 N0 M0 colorectal carcinoma because there is only a small difference in microvessel frequency between patients with widely different survival times.

Distribution of iron in the liver predicts the response of chronic hepatitis C infection to interferon therapy.

Recent evidence suggests that patients with chronic hepatitis C virus (CHCV) who respond to interferon-alpha (IFN) therapy have a lower hepatic iron concentration than those who do not. The object of this study was to assess the concentration and distribution of iron in liver biopsies from 15 patients with CHCV seen at the authors' medical center between June 1992 and March 1993. Patients with complete response to IFN were compared to those with non-complete response with respect to quantitative hepatic iron concentration, serum iron indices, and a detailed analysis of histologic features of hematoxylin-and-eosin and iron-stained pre-IFN biopsies. Patients with non-complete response had significantly higher scores for stainable iron in sinusoidal cells (P = .02) and portal tracts (P = .05) than did patients with complete response. Total hepatic iron scores, mean quantitative hepatic iron, and mean serum ferritin were higher in patients with noncomplete response, but the differences were not significant. In conclusion, iron deposition in sinusoidal cells and portal tracts is significantly less frequent in patients with complete response to IFN than in those with poor or no response, and may be a useful, objective predictor of response to IFN therapy.

Ubiquitin as a marker of cell injury in nonalcoholic steatohepatitis.

Ubiquitin (UB), an intracellular protein that binds to other proteins to target them for proteolysis, is associated with Mallory hyalin (MH), which supports a biopsy diagnosis of nonalcoholic steatohepatitis (NASH). We analyzed 54 liver biopsy specimens from 49 patients with a clinical diagnosis of NASH for immunoreactive UB and multiple features of necroinflammation, fibrosis, and Prussian blue-positive iron to determine whether the presence of immunoreactive UB increases detection of MH or correlates with other features of cell injury or mutations of the HFE gene. MH and UB were graded. Analysis for HFE gene mutations was performed in 48 patients. Biopsy diagnoses were distributed as follows: NASH, 42; steatosis, 10; and nonspecific changes, 2. UB was present in 20 specimens and MH in 23. Of 31 specimens with 0 MH, 6 had UB; of 14 with 1 + (questionable) MH, 7 had 1+ or 2+ UB. UB correlated positively and significantly with the diagnosis and grade of NASH, presence of MH, cell swelling, lobular inflammation, and fibrosis. Immunostaining for UB may enhance detection of MH in questionable cases, support the diagnosis of NASH, and indicate which patients may be at risk for progression of disease.

Multiparameter flow cytometric analysis of colon polyps.

Sixty-eight colonic polyps of various histologic types were studied using retrospective flow cytometric (FCM) DNA analysis to determine the prevalence of aneuploid cell populations and whether they were associated with any particular histologic features. Overall, 13 of 68 polyps (19%) contained DNA-aneuploid cells, including 3 of 9 villous and 4 of 10 villoglandular polyps with histologic features of carcinoma in situ (CIS), 4 of 11 villous and 1 of 18 villoglandular polyps without CIS, and 1 of 12 adenomatous polyps. Eight hyperplastic polyps were diploid. These results show retrospective FCM analysis can detect DNA aneuploidy in polyps; DNA aneuploidy may occur before histologic evidence of invasive carcinoma; and this change is more frequent in types of polyps thought to have increased malignant potential (i.e., those with villous morphology and/or CIS).

Invariant chain expression in colon neoplasms.

Invariant chain (Ii) is a chaperone molecule that inhibits binding of endogenous antigens to class II molecules. High levels of Ii in cancer cells may prevent tumour antigen expression with class II and render the tumour less immunogenic. To correlate the expression of Ii and class II molecules in colon carcinomas with the density of tumour infiltrating lymphocytes (TILs), surgical specimens from a total of 48 patients with well-(WDAC), moderately (MDAC) and poorly differentiated adenocarcinomas (PDAC), adenoma with high-grade dysplasia (AdHGD) and adenomas were immunostained for Ii and class II antigen (HLA-DR). Aggregates of TILs were graded in H&E-stained sections. Normal colon epithelium was negative for Ii and HLA-DR. Invasive carcinomas showed a linear increase in the expression of Ii in the progression from low- to high-grade tumours, while there was no significant difference in HLA-DR expression across the groups. Invasive carcinomas showed a disproportionate increase in Ii over HLA-DR. Frequency of TILs showed inverse correlation with expression of Ii and tumour grade. This is the first demonstration that expression of Ii increases in the progression from low- to high-grade colon neoplasms and is most marked in the poorly differentiated carcinomas. Ii expression by carcinomas is inversely related to the frequency of TILs. The findings suggest that increased Ii renders the tumour less immunogenic and less likely to stimulate a host immune response.

Effect of interferon therapy on bile duct inflammation in hepatitis C.

Inflammation of the bile ducts was studied in liver biopsies from patients with chronic hepatitis C to determine whether the frequency of inflamed bile ducts changes with therapy and correlates with other histological variables and expression of class I and II MHC antigens on ductal epithelium. Twenty patients treated at UMMC between 1991 and 1994 underwent needle biopsies of the liver before and after therapy with interferon alpha 2B (IFN). A complete response to therapy was defined as a return to normal serum alanine aminotransferase levels occurring and persisting during therapy. The number of inflamed bile ducts/total ducts (%IBDs), presence of piecemeal necrosis and lymphoid aggregates, and grade of inflammation were assessed in each high-power field in all areas with bile ducts. The frequencies of these variables were compared in cirrhotics and non-cirrhotics and in patients with complete or incomplete responses to IFN. Frozen sections of biopsies from 5 patients were immunostained using antibodies to HLA-DR and B-2 microglobulin, and positive staining was noted on bile ducts. Before therapy, the %IBD was slightly greater in patients with cirrhosis. After IFN, both %IBD and serum alkaline phosphatase levels decreased in non-cirrhotics who responded to IFN. The change in frequency of IBD with IFN paralleled the changes in the other histological features. No correlation was noted between bile duct inflammation and expression of class I and II antigens. The conclusion is that inflammation of the bile ducts occurs frequently in chronic hepatitis C, correlates with other features of inflammation in the triads, and decreases in response to IFN therapy.

Inflammatory markers in chronic hepatitis C.

To test the hypothesis that inflammation in hepatitis C follows mechanisms common to immune-activated pathways, the distributions of T and B cells, adhesion molecules and transforming growth factor-beta (TGF-beta) were assessed in liver biopsies with chronic inflammation due to hepatitis C (HCV, n = 8) and other causes (non-HCV, n = 10). Frozen sections were immunostained using primary antibodies to CD2, CD20, CD4, CD8, intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM)-1, HLA-DR, lymphocyte function-associated antigen (LFA)-1, and TGF-beta. Inflammatory cells positive for each immunophenotypic marker were counted, and positive staining for adhesion molecules, HLA-DR and TGF beta was graded in triads and lobules and compared in HCV and non-HCV biopsies. In all biopsies, T cells were more frequent than B cells, both in triads and lobules. CD20+, CD4+, CD8+ and LFA-1+ cells were increased in HCV compared to non-HCV biopsies. Portal lymphoid aggregates were present in 6 of 8 HCV biopsies and 3 of 10 non-HCV biopsies. Aggregates consisted of CD20+, CD4+, CD8+ and LFA-1+ cells, and ICAM-1 and VCAM-1 were increased. Sinusoidal lining cells in HCV biopsies and non-HCV biopsies with inflammation expressed HLA-DR, ICAM-1, and CD4. TGF-beta was increased in foci of necrosis. Inflammation in chronic HCV involves common immune-mediated cellular effector pathways and the inflammation in the portal triads represents aggregation of both T and B cells, mediated in part by upregulation of adhesion molecules on portal stromal cells; this is possibly in response to antigens draining from necroinflammatory foci in the lobules. TGF-beta is increased in active necroinflammatory foci, but not in portal lymphoid aggregates.

Sonographic characteristics of epidermoid cyst of testicle.

The ultrasonographic characteristics of an epidermoid cyst of the testicle are presented. Since these findings are similar to other published case reports, preoperative sonographic diagnosis of this lesion may be possible.

Bosentan, an endothelin antagonist, augments hepatic graft function by reducing graft circulatory impairment following ischemia/reperfusion injury.

Endothelin is a potent hepatic vasoconstrictor. We evaluated the role of an endothelin antagonist in hepatic ischemia/reperfusion injury. Bosentan, a novel endothelin receptor antagonist, was infused directly into the portal vein prior to cold ischemia and immediately on reperfusion, in five porcine livers. Five other pigs underwent routine liver harvest and reperfusion without bosentan treatment. Hepatic vascular resistance and liver tissue blood flow, as measured by thermistor flow probes, were determined following reperfusion. Hepatocellular damage was assessed through hepatic venous levels of sorbitol dehydrogenase and lactate dehydrogenase. Endothelial cell damage was determined in sections immuno-stained for factor VIII. Graft function was determined through oxygen consumption, bile production, and response to bile acid challenge. Organs treated with bosentan demonstrated lower vascular resistance and enhanced tissue blood flow (P < 0.05) as compared to untreated organs. Portal vein inflow to hepatic tissue was significantly enhanced (4.4-fold) in the bosentan-treated organs (P < 0.05). No difference was observed in hepatocellular damage. Pathology scores for factor VIII immunohistochemical staining were 2.3-fold higher in the bosentan-treated livers as compared to untreated livers (P < 0.05). The bosentan-treated livers also demonstrated enhanced oxygen consumption, increased bile production, and augmented biliary response to a bile acid challenge (P < 0.05). These results indicate that administration of bosentan before and after ischemia/reperfusion reduces hepatic circulatory disturbances, diminishes endothelial cell damage, and augments hepatic graft function.

p53: a good diagnostic marker for intratubular germ cell neoplasia, unclassified.

Intratubular germ cell neoplasia, unclassified (IGCNU) is a precursor of germ cell tumors (GCT) of the testis. In routine histologic sections, neoplastic intratubular germ cells may be very few and easily overlooked. The aim of this study is two-fold: to establish the immunohistochemical pattern of expression of p53 in IGCNU and GCT and to determine whether p53 can be used as a marker for IGCNU. Resection specimens from 14 seminomas, 14 mixed germ cell tumors (MGCT), 3 embryonal carcinomas, 2 mature teratomas, 7 IGCNUs, and 11 normal testes were stained for p53. Normal germ cells and Sertoli cells of the seminiferous tubules in all normal testes were negative for p53. The tumor cells of all IGCNU cases were positive for p53. All invasive components of mixed germ cell tumors, embryonal carcinomas, and seminomas exhibited expression of p53. Mature teratoma components were negative for p53. These findings indicate that p53 is a highly sensitive marker of IGCNU and highly specific in distinguishing lesional tissue from normal seminiferous tubules. The current findings also suggest that p53 may be involved as an early step in the malignant progression of most germ cell neoplasias.

Hepatic granulomas following ileal bypass for obesity.

A review of liver biopsy specimens from patients undergoing ileojejunal bypass for obesity showed granulomas in follow-up biopsy specimens from six of 25 patients (24%) three months to four years after the procedure. The incidence was significantly greater than that seen in obese patients at the time of surgery (4%), (P less than .02). Their origin could not be attributed to systemic infections, medications, or nutritional factors. It would seem that hepatic granulomas in such patients may be due to factors associated with the surgical procedure.

Expression of cytokeratins 7 and 20 in carcinomas of the extrahepatic biliary tract, pancreas, and gallbladder.

BACKGROUND: Expression of cytokeratins 7 (CK7) and 20 (CK20) may help distinguish the site of origin for metastatic carcinomas. Little is known regarding their expression in biliary tract and pancreatic carcinomas. Our aim was to study the expression of CK7 and CK20 in these tumors. DESIGN: Fifty-three carcinomas of the extrahepatic bile ducts (n = 8), ampulla of Vater (n = 7), gallbladder (n = 11), and pancreas (n = 27), were retrieved from the surgical pathology files of the University of Massachusetts Medical Center. Formalin-fixed, paraffin-embedded sections were immunostained with mouse monoclonal antibodies to CK7 and CK20 using an avidin-biotin immunoperoxidase technique with microwave antigen retrieval. The percentage of cells positive for each antibody was assessed on a scale of 0 to 3 (0, <10%; 1+, 10% to 50%; 2+, 51% to 90%; 3+, >90%). RESULTS: The majority of carcinomas in all groups were positive for CK7 (CK7+) and negative for CK20 (CK20-). Of the CK7+ tumors, the majority of tumors in each group were 3+ positive. CONCLUSIONS: (1) Carcinomas of the extrahepatic biliary tract and pancreas are strongly positive for CK7 and negative for CK20 and can be included in the differential diagnosis of other carcinomas with this profile in metastatic sites. (2) The CK7/CK20 immunostaining profile will not identify the site of origin for tumors with extensive growth in the porta hepatis region.

Intraductal papillary mucinous neoplasm of the pancreas presenting as acute pancreatitis.

Intraductal papillary mucinous neoplasms are rare pancreatic exocrine tumors with distinct clinicopathologic features. They usually present with a long history of chronic pancreatitis-like symptoms, which are often associated with weight loss, diarrhea, and malabsorption. We report a case of benign intraductal papillary mucinous neoplasm with focal squamous metaplasia presenting as acute necrotizing pancreatitis. The clinicopathologic features are discussed in a brief review of the literature.

An immunostaining panel for diagnosis of malignancy in mucinous tumors of the pancreas.

BACKGROUND: The diagnosis of malignancy in pancreatic mucinous cystic tumors depends on demonstrating invasion that may be focal and require extensive sectioning. OBJECTIVE: To explore markers that may indicate malignant potential in mucinous cystic tumors. DESIGN: Routinely processed sections from resected specimens of 12 normal pancreata, 14 pancreata with chronic pancreatitis, 9 mucinous cystic tumors, and 30 invasive adenocarcinomas were immunostained with antibodies to p53, HER-2/neu, epithelial growth factor receptor (EGFR), transforming growth factor alpha (TGF-alpha), and Ki-67. RESULTS: Expression of p53, HER-2/neu, and Ki-67 was significantly more frequent in mucinous tumors than in normal pancreatic tissue and chronic pancreatitis tissue (P =.0003 to.05). Strong expression (more than one third of cells positive) and strong intensity (2+ and 3+) of staining of p53 and EGFR were seen only in carcinomas. Coexpression of p53/HER-2/neu and EGFR/HER-2/neu and a frequency of Ki-67+ nuclei of greater than 5% of cells discriminated between mucinous tumors and normal pancreatic tissue and chronic pancreatitis tissue. p53 expression was significantly more frequent in carcinomas than in mucinous tumor (P =.0326). Coexpression of p53/EGFR discriminated between mucinous tumors and carcinomas; however, TGF-alpha was not discriminative. CONCLUSIONS: The immunostaining panel of p53, HER-2/neu, Ki-67, and EGFR can be helpful in indicating malignant potential in mucinous tumors of pancreas in routine pathology practice.