A morpho-molecular prognostic model for hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is the third common cause of cancer-related deaths and its prognostication is still suboptimal. The aim of this study was to establish a new prognostication algorithm for HCC. METHODS: In all, 13 biomarkers related to the etiopathogenesis of HCC were evaluated by immunohistochemistry using tissue microarrays containing 121 primary HCC resection cases, and validated in subsequent cohort of 85 HCC cases. The results were compared with Affymetrix Gene Chip Human Genome U133Plus microarray data in a separate cohort of 228 HCC patients. RESULTS: On immunohistochemical evaluation and multivariate Cox regression analysis p53, alpha fetaprotein (AFP), CD44 and CD31, tumour size and vascular invasion, were significant predictors for worse survival in HCC patients. A morpho-molecular prognostic model (MMPM) was constructed and it was a significant independent predictor for overall survival (OS) and relapse-free survival (RFS) (P<0.000). The OS and RFS of HCC(low) was higher (104 and 78 months) as compared with HCC(high) (73 and 43 months) (P<0.000 for OS and RFS). Hepatocellular carcinoma patients with higher stage (III+IV), >5 cm tumour size, positive vascular invasion and satellitosis belonged to HCC(high) group. The validation group reproduced the same findings. Gene expression analysis confirmed that 7 of the 12 biomarkers were overexpressed in >50% of tumour samples and significant overexpression in tumour samples was observed in AFP, CD31, CD117 and Ki-67 genes. CONCLUSION: The MMPM, based on the expression of selected proteins and clinicopathological parameters, can be used to classify HCC patients between good vs poor prognosis and high vs low risk of recurrence following hepatic resection.

Factors determining the remission of microprolactinomas after dopamine agonist withdrawal.

BACKGROUND: Withdrawal of dopamine agonist (DA) therapy in the management of microprolactinoma is common practice, but it is unclear which patients are likely to attain long-term remission. OBJECTIVE: To identify predictive factors for long-term remission. DESIGN: Prospective cohort study. PATIENTS: Forty subjects (39 female, aged 24-60 years) with microprolactinoma; all had been normoprolactinaemic on DA therapy for at least 2 years [mean duration of therapy 9 years (range 2-27)]. MEASUREMENTS: A pituitary magnetic resonance imaging (MRI) was performed on 36 (90%) subjects before DA withdrawal. Relapse was defined as prolactin greater than 480 mIU/l (22.8 microg/l) on two occasions. RESULTS: Nine out of 40 (22.5%) subjects were normoprolactinaemic 12 months after DA withdrawal. Amongst the relapse group, 24 of 31 subjects (79.4%) had already relapsed at 3 months. Normalization of MRI prior to DA withdrawal (P = 0.0006) and longer duration of DA treatment (P = 0.032) were significant predictors of remission. Age, pre-treatment prolactin, nadir prolactin, previous failure of DA withdrawal, pregnancy, dose and type of DA were not significant predictors of remission. The nine patients who were in remission at 12 months were then followed up for 58.0 +/- 5.8 months; all remained in remission. CONCLUSIONS: As many as 22.5% of subjects with microprolactinoma remained normoprolactinaemic 12 months after DA withdrawal and these subjects stayed in remission for up to 5 years. Significant predictive factors were normalization of MRI prior to discontinuation, and duration of DA treatment. Our findings support intermittent DA withdrawal after a period of normoprolactinaemia, particularly where MRI appearances have normalized.

Near-infrared Raman spectroscopy for early diagnosis and typing of adenocarcinoma in the stomach.

BACKGROUND: The aim of this study was to evaluate the feasibility of using near-infrared (NIR) Raman spectroscopy for early diagnosis and typing of intestinal and diffuse adenocarcinoma of the stomach. METHODS: A dispersive-type NIR Raman system was used for tissue measurements. One hundred gastric tissue samples from 62 patients who underwent endoscopy or gastrectomy were used (70 normal tissue specimens and 30 adenocarcinomas). Principal components analysis (PCA) and multinomial logistic regression (MNLR) were used to develop diagnostic algorithms for tissue classification. RESULTS: High-quality Raman spectra ranging from 800 to 1800 cm(-1) were acquired from gastric tissue within 5 s. There were significant differences in Raman spectra between normal stomach and the two gastric adenocarcinoma subtypes, particularly in the spectral ranges 850-1150, 1200-1500 and 1600-1750 cm(-1), which contain signals related to proteins, nucleic acids and lipids. PCA-MNLR achieved predictive accuracies of 88, 92 and 94 per cent for normal stomach, and intestinal- and diffuse-type gastric adenocarcinomas respectively. CONCLUSION: NIR Raman spectroscopy can detect gastric malignancy and identify the subtype of gastric adenocarcinoma.

The interferon stimulated gene viperin, restricts Shigella. flexneri in vitro.

The role of interferon and interferon stimulated genes (ISG) in limiting bacterial infection is controversial, and the role of individual ISGs in the control of the bacterial life-cycle is limited. Viperin, is a broad acting anti-viral ISGs, which restricts multiple viral pathogens with diverse mechanisms. Viperin is upregulated early in some bacterial infections, and using the intracellular bacterial pathogen, S. flexneri, we have shown for the first time that viperin inhibits the intracellular bacterial life cycle. S. flexneri replication in cultured cells induced a predominantly type I interferon response, with an early increase in viperin expression. Ectopic expression of viperin limited S. flexneri cellular numbers by as much as 80% at 5hrs post invasion, with similar results also obtained for the intracellular pathogen, Listeria monocytogenes. Analysis of viperins functional domains required for anti-bacterial activity revealed the importance of both viperin's N-terminal, and its radical SAM enzymatic function. Live imaging of S. flexneri revealed impeded entry into viperin expressing cells, which corresponded to a loss of cellular cholesterol. This data further defines viperin's multi-functional role, to include the ability to limit intracellular bacteria; and highlights the role of ISGs and the type I IFN response in the control of bacterial pathogens.

Upregulation of HIF-1alpha in malignant transformation of oral submucous fibrosis.

BACKGROUND: Oral submucous fibrosis (OSF) is a precancerous condition showing extensive fibrosis of the submucosa and affects most parts of the oral cavity, including pharynx and upper third of the oesophagus. The molecules involved in the biological pathways of the fibrotic process appeared to be either down- or upregulated at different stages of the disease. Despite the precancerous nature, malignant transformation of the epithelium in the background of fibrosis has not been studied in detail. HIF-1alpha is a known transcription factor that is induced by hypoxia. AIMS: To test the hypothesis that hypoxia plays a role in malignant transformation and progression of OSF. MATERIALS AND METHODS: We used both formalin-fixed and frozen samples of OSF and normal mucosa to investigate the relationship between HIF-1alpha and epithelial dysplasia using immunohistochemistry and RT-PCR. CONCLUSIONS: Our data indicate that HIF-1alpha is upregulated at both protein and mRNA levels in OSF and the correlation with epithelial dysplasia is statistically significant (P < 0.001). We propose that HIF-1alpha may play a role in malignant transformation of OSF. Further, over-expression of HIF-1alpha may contribute to the progression of fibrosis. It may be possible to use HIF-1alpha as a marker for malignant transformation of OSF.

Fingerprinting genomic instability in oral submucous fibrosis.

BACKGROUND: Oral submucous fibrosis (OSF) is a high-risk pre-cancerous condition where 7-13% of these patients develop head and neck squamous cell carcinoma (HNSCC). To date there is no cancer predictive markers for OSF patients. Genomic instability hallmarks early genetic events during malignant transformation causing loss of heterozygosity (LOH) and chromosomal copy number abnormality. However, to date there is no study on genomic instability in OSF. Although this condition is known as a high-risk pre-cancerous condition, there is no data regarding the genomic status of this disease in terms of genetic susceptibility to malignant transformation. METHODS: In this study, we investigated the existence of genetic signatures for carcinogenesis in OSF. We employed the high-resolution genome-wide Affymetrix Mapping single nucleotide polymorphism microarray technique to 'fingerprint' global genomic instability in the form of LOH in 15 patient-matched OSF-blood genomic DNA samples. RESULTS: This rapid high-resolution mapping technique has revealed for the first time that a small number of discrete hot-spot LOH loci appeared in 47-53% of the OSF tissues studied. Many of these LOH loci were previously identified regions of genomic instability associated with carcinogenesis of the HNSCC. CONCLUSION: To our knowledge, this is the first evidence that genomic instability in the form of LOH is present in OSF. We hypothesize that the genomic instability detected in OSF may play an important role in malignant transformation. Further functional association studies on these putative genes may reveal potential predictive oral cancer markers for OSF patients.

Fumes from meat cooking and lung cancer risk in Chinese women.

Chinese women are recognized to have a high incidence of lung cancer despite a low smoking prevalence. Several studies have implicated domestic exposure to cooking fumes as a possible risk factor, although the exact carcinogens have yet to be identified. Heterocyclic amines are known carcinogens, which have been identified in cooked meat, and also in fumes generated during frying or grilling of meats. We conducted a case-control study of 303 Chinese women with pathologically confirmed, primary carcinomas of the lung and 765 controls to examine the association between exposure to meat cooking and lung cancer risk. Data on demographic background, smoking status, and domestic cooking exposure, including stir-frying of meat, were obtained by in-person interview while in hospital. The response rates among eligible cases and controls were 95.0 and 96.9%, respectively. The proportion of smokers (current or ex-smokers) among cases and controls was 41.7 and 13.1%, respectively. Adenocarcinomas comprised 31.5% of cancers among smokers and 71.6% among nonsmokers. When cases were compared with controls, the odds ratio (OR) for lung cancer (all subtypes) among ex-smokers was 4.3 [95% confidence interval (CI) 2.7-6.8] and that among current smokers was 5.0 (95% CI, 3.4-7.3). Among smokers, women who reported that they stir-fried daily in the past had a significantly increased risk of lung cancer (adjusted OR, 2.0; 95% CI, 1.0-3.8) and among these women, risk was enhanced for those who stir-fried meat daily (OR, 2.7; 95% CI, 1.3-5.5). Women who stir-fried daily but cooked meat less often than daily did not show an elevated risk (OR, 1.0. 95% CI, 0.5-2.4). Risk was further increased among women stir-frying meat daily who reported that their kitchen was filled with oily fumes during cooking (OR, 3.7; 95% CI, 1.8-7.5). These cooking practices on their own did not increase risk among nonsmokers in our study population. Our results suggest that inhalation of carcinogens, such as heterocyclic amines generated during frying of meat, may increase the risk of lung cancer among smokers. Further studies in different settings are warranted to examine this possibility, which may also help to explain the higher risk observed among women smokers compared with men.

Dietary isothiocyanates, glutathione S-transferase -M1, -T1 polymorphisms and lung cancer risk among Chinese women in Singapore.

Chinese populations consume a diet relatively high in isothiocyanates (ITCs), a derivative of cruciferous vegetables known to have cancer-protective effects. This class of compounds is metabolized by the glutathione S-transferase family of enzymes, which are also involved in the detoxification of tobacco-related carcinogens such as polycyclic aromatic hydrocarbons and alkyl halides. We evaluated the association between dietary isothiocyanate intake, GSTM1 and GSTT1 polymorphisms, and lung cancer risk in 420 Chinese women: 233 histologically confirmed lung cancer patients and 187 hospital controls. Among these, 58.8% of cases and 90.3% of controls were lifetime nonsmokers. An allele-specific PCR method was used to detect the presence or absence of the GSTM1 and GSTT1 genes in DNA isolated from peripheral blood. Higher weekly intake of ITCs (above the control median value of 53.0 micromol) reduced the risk of lung cancer to a greater extent in smokers [adjusted odds ratio (OR), 0.31; 95% confidence interval (CI), 0.10-0.98] than nonsmokers (OR, 0.70; 95% CI, 0.45-1.11). The inverse association was stronger among subjects with homozygous deletion of GSTM1 and/or GSTT1. Among nonsmokers with GSTM1-null genotype, higher intake of ITCs significantly reduced the risk of lung cancer (OR, 0.54; 95% CI, 0.30-0.95), an effect not seen among those with detectable GSTM1 (OR, 1.07; 95% CI, 0.50-2.29). Our results, in a Chinese female population, are consistent with the hypothesis that ITC is inversely related to the risk of lung cancer, and we show that among nonsmokers this effect may be primarily confined to GST-null individuals. Conjugation and elimination of ITCs is enhanced in GST-non-null relative to -null individuals, such that the GST metabolic genotype modifies the protective effect of ITCs on lung cancer development.

Mapping the melatonin receptor. 6. Melatonin agonists and antagonists derived from 6H-isoindolo[2,1-a]indoles, 5,6-dihydroindolo[2,1-a]isoquinolines, and 6,7-dihydro-5H-benzo[c]azepino[2,1-a]indoles.

6H-Isoindolo[2,1-a]indoles (5, 7, 10, 13), 5,6-dihydroindolo[2, 1-a]isoquinolines (20, 21), and 6,7-dihydro-5H-benzo[c]azepino[2, 1-a]indoles (23, 25, 27, 30) have been prepared as melatonin analogues to investigate the nature of the binding site of the melatonin receptor. The affinity of analogues was determined in a radioligand binding assay using cloned human mt(1) and MT(2) receptor subtypes expressed in NIH 3T3 cells. Agonist and antagonist potency was measured using the pigment aggregation response of a clonal line of Xenopus laevis melanophores. The 2-methoxyisoindolo[2, 1-a]indoles (7a-d) showed much higher binding affinities than the parent isoindoles (5a-e), and whereas 7a-c were agonists in the functional assay, 7d and 5a-e were antagonists. The 2-ethoxyisoindolo[2,1-a]indoles (10a-d) showed reduced binding affinities compared to their methoxy analogues, while the 5-chloro derivative 13 showed a considerable reduction in binding affinity and potency compared to 7a. The 10-methoxy-5,6-dihydroindolo[2, 1-a]isoquinolines (21a-c) had higher binding affinities than the corresponding parent indoloisoquinolines (20a-c) in the human receptor subtypes, and the parent compounds were antagonists whereas the 10-methoxy derivatives were agonists in the functional assay. The N-cyclobutanecarbonyl derivatives of both the parent (20d) and 10-methoxyl (21d) series had similar binding affinities and were both antagonists with similar potencies. The 11-methoxy-6, 7-5H-benzo[c]azepino[2,1-a]indoles (25a-d) had higher binding affinities than the corresponding parent compounds (23a-d) at the MT(2) receptor but similar affinities at the mt(1) site; all of the compounds were antagonists in the functional assay. Changing 11-methoxy for 11-ethoxy decreased the binding affinity slightly, and this was more evident at the MT(2) receptor. All of the derivatives investigated had either the same or a greater affinity for the human MT(2) receptor compared to the mt(1) receptor (range 1:1-1:132). This suggests that the mt(1) and MT(2) receptor pockets differ in their ability to accommodate alkyl groups in the indole nitrogen region of the melatonin molecule. Two compounds (7c and 25c) were tested in functional assays on recombinant mt(1) and MT(2) melatonin receptors. Compound 7c is a potent agonist with some selectivity (44-fold) for the MT(2) receptor, while 25c is an MT(2)-preferring antagonist. Increasing the carbon chain length between N-1 of indole and the 2-phenyl group from n = 1 through n = 3 leads to a fairly regular decrease in the binding affinity, but, remarkably, when n = 3, it converts the methoxy compounds from melatonin agonists to antagonists. The Xenopus melatonin receptor thus cannot accommodate an N-n-alkyl chain attached to a 2-phenyl substituent with n > 2 in the required orientation to induce or stabilize the active receptor conformation.

Mapping the melatonin receptor. 5. Melatonin agonists and antagonists derived from tetrahydrocyclopent[b]indoles, tetrahydrocarbazoles and hexahydrocyclohept[b]indoles.

Tetrahydrocyclopent[b]indoles, tetrahydrocarbazoles, and hexahydrocyclohept[b]indoles have been prepared as melatonin analogues to investigate the nature of the binding site of the melatonin receptor. The affinity of analogues was compared in a radioligand binding assay using chicken brain membranes and agonist and antagonist potency measured in clonal Xenopus laevis melanophore cells. Comparison of the N-acyl-3-amino-6-methoxytetrahydrocarbazoles (2) with N-acyl-4-(aminomethyl)-6-methoxy-9-methyltetrahydrocarbazoles (9) showed that the latter have much higher binding affinities for the chicken brain receptor. Comparison of N-acyl-1-(aminomethyl)-7-methoxy-4-methyltetrahydrocyclopent[b]ind oles (10), 6-methoxytetrahydrocarbazoles (9), and N-acyl-10-(aminomethyl)-2-methoxy-5-methylhexahydrocyclohept[b]ind oles (11) showed that the tetrahydrocarbazoles had the highest binding affinity with the cyclohept[b]indoles and the cyclopent[b]indoles having rather lower affinities. All of these observations are in agreement with our postulated model of melatonin orientation at the binding pocket in which the 3-amidoethane side chain is in a conformation close to the 5-methoxyl group, as is shown in the X-ray crystallographic structure of 9m and in the energy-minimized computed structures. Separation of the enantiomers of members from each of these three systems was accomplished by chiral HPLC. It was found that in all cases the (-)-enantiomer had a higher binding affinity than the (+)-enantiomer. An X-ray crystallographic analysis of the two enantiomers of 9a showed that the (+)-enantiomer had the (R) absolute stereochemistry. Since the sign of the Cotton curves, determined from circular dichroism studies, was the same for all (+)-enantiomers, it is assumed that the absolute stereochemistry at these centers is identical. In the Xenopus melanophore assay, the tetrahydrocarbazoles 2 (R = H) were mainly weak antagonists, while those with R = OMe were agonists. The biological behavior of the tetrahydrocarbazoles 9 (R = H) depended on R1, some being agonists and some antagonists, whereas those with R = OMe were generally agonists. Variation of the R and R1 groups in compounds of type 9 produced both agonists and antagonists. The tetrahydrocylopentaindoles 10 had similar biological properties to the corresponding analogues of 9, but the hexahydrocycloheptaindoles 11 showed a much greater propensity to be antagonists. In all cases the (S)-enantiomers were found to be more potent agonists than the (R)-enantiomers.

An endogenous 5-HT(7) receptor mediates pigment granule dispersion in Xenopus laevis melanophores.

Melatonin (5-methoxy N-acetyltryptamine) and serotonin (5-HT) exert rapid, but opposite effects on pigment granule distribution in Xenopus laevis melanophores. Low concentrations of melatonin (10(-11) - 10(-9) M) cause a dramatic perinuclear aggregation of the melanin-containing granules, while 5-HT (10(-8) - 10(-5) M) disperses pigment granules throughout the cell. The present study found that pharmacological doses of melatonin (> or =10(-6) M) induced a time- and concentration-dependent pigment granule dispersion, which was mediated by an endogenous melanophore 5-HT receptor. 5-HT produced a concentration-dependent elevation of melanophore cyclic AMP, and 5-HT-induced dispersion was blocked by H89 (10(-4) M), an inhibitor of protein kinase A (PKA), but not by a PKC inhibitor (Ro 31-8220, 10(-5) M), indicating a vital role for cyclic AMP in 5-HT-induced dispersion. 5-HT-mediated dispersion was not blocked by antagonists selective for G(s)-coupled 5-HT(4) (GR113808) or 5-HT(6) (Ro 04-6790, Ro 63-0563, olanzepine) receptors, nor by 5-HT(1 - 3) (pindolol, ketanserine, metoclopramide, MDL72222, tropisetron) receptor antagonists, but was inhibited by a selective 5-HT(7) receptor antagonist, DR4004, and other antagonists with a high affinity for 5-HT(7) receptors. The rank order of antagonist potency was: risperidone (mean pK(B) 7.82)>methiothepin (7.43)>DR4004 (6.92)>mesulergine (6.83)>methysergide (6.60)>[+/-]-sulpiride (5.81)>spiperone (5.52). The agonist potency order [mean pEC(50), 5-CT (8.68)>5-HT (7.13)>5-MT (6.94)>8-OH-DPAT (4.79)>sumatriptan (<4)] was also consistent with an action on 5-HT(7) receptors. RT - PCR confirmed that melanophores express 5-HT(7) receptor mRNA. The pigment dispersing effect of high melatonin concentrations in melanophores is most likely mediated by activation of 5-HT(7) receptors. Conceivably some of the effects attributed to pharmacological doses of melatonin in mammals may be mediated by activation of 5-HT(7) receptors.

The putative melatonin receptor antagonist GR128107 is a partial agonist on Xenopus laevis melanophores.

1. GR128107 (3-(1-acetyl-3-methyl-piperidine)-5-methoxyindole) has previously been reported to be a competitive melatonin receptor antagonist in blocking melatonin inhibition of [3H]-dopamine release from rabbit retina, a response mediated by the MT2 receptor subtype. 2. GR128107, like melatonin, induced a rapid (maximum response in 60-90 min) pigment aggregation in a clonal line of Xenopus laevis melanophores. GR128107 behaved as a partial agonist (pEC50 8.58+/-0.03, n=3) with an Emax of 0.83 (relative to melatonin, pEC50 10.09+/-0.03, n=3). 3. The concentration-response curve for pigment granule aggregation to both melatonin and GR128107 was displaced in a parallel, rightward manner by melatonin receptor antagonists with very similar potencies; estimated pKB RJ252 (against melatonin 4.60/against GR128107 4.54) < GR135533 (6.40/6.14) < Luzindole (6.45/6.49) < S20929 (6.58/6.65) < 4-P-PDOT (6.73/6.85). 4. Both melatonin- and GR128107-induced pigment granule aggregation was prevented by pretreatment of melanophores with pertussis toxin (10-1000 ng ml(-1)). 5. Prolonged pre-treatment of melanophores with melatonin desensitized the pigment aggregation response to GR128107. In desensitized cells, the maximal aggregation produced by GR128107 was only 0.27+/-0.01 (n=4) and the pEC50 was reduced (vehicle 8.57+/-0.12; melatonin pre-treated 7.84+/-0.09, n=4). The maximal response to melatonin in desensitized melanophores was unchanged but the pEC50 was reduced (vehicle 10.49+/-0.03; melatonin pre-treated 9.83+/-0.04, n=4). 6. These results demonstrate that GR128107 induces pigment granule aggregation in Xenopus melanophores by activating a cell membrane melatonin receptor coupled via a pertussis toxin-sensitive G-protein. 7. The partial agonist activity of GR128107 in melanophores may be apparent because of the very high density of melatonin receptors in these cells (Bmax 1223 fmol mg protein(-1)) compared to the low density of sites in rabbit retina (Bmax 3.1 fmol mg protein(-1)). This suggestion is supported by the finding that GR128107, like melatonin, acted as a full agonist and inhibited forskolin-stimulation of cyclic AMP accumulation in NIH-3T3 cells expressing a high density of human mt1 or MT2 receptors.

Clinical importance of p53 protein in gall bladder carcinoma and its precursor lesions.

AIMS: To study the expression and importance (if any) of p53 protein in gall bladder carcinoma and its precursor lesions. METHODS: Immunohistochemical staining was performed on formalin fixed, paraffin wax embedded histological sections with an anti-human p53 monoclonal antibody (DO-7; Dako Corporation M7001) (24 carcinomas, one adenocarcinoma in situ, six dysplasias, three adenomas and four cases of chronic cholecystitis). Invasive, in situ, and dysplastic areas as well as normal-looking epithelium were sought. Nuclear staining was assessed according to intensity and extent of positive cells. Both variables were graded on a scale of 1-3 and aggregate p53 scores were obtained (range: 0, 2-6). Only p53 scores of > or = 3 were regarded as significant. RESULTS: Clinically important amounts of p53 were expressed in 92% of invasive carcinomas, 86% of carcinoma in situ, and 28% of dysplastic areas. None of the adenomas contained clinically important amounts of p53. Normal epithelium, present in all the cases, did not express p53 except in one case of moderately differentiated adenocarcinoma (p53 score 3). In general, there was no difference in the prevalence of p53 protein expression between dysplasias associated with, and those unassociated with invasive disease. There was a tendency for higher grade carcinomas to express more p53 protein. CONCLUSIONS: The distribution of p53 protein in invasive carcinomas and the adjacent dysplastic and preinvasive lesions suggests that it is more commonly expressed than previously thought. The fact that p53 protein is also expressed in cases of dysplasia and carcinoma in situ unassociated with invasive malignancy lends further support to the contention that p53 gene mutations may have a role in the pathogenesis of gall bladder cancer. Expression of p53 protein may possibly be an indication of likely disease progression from dysplasia, to carcinoma in situ, to invasive disease.

Association of Helicobacter pylori with HLA-DR antigen expression in gastritis.

AIMS: To assess the association between Helicobacter pylori-associated gastritis and HLA-DR antigen (class II antigen) expression. METHODS: Fifty endoscopic gastric biopsy specimens were studied for the presence of H pylori, degree and type of inflammation, and for HLA-DR antigen expression in the epithelium. The cases were chosen to represent different categories: inflamed gastric mucosa with (n = 13) and without (n = 20) H pylori, and non-inflamed mucosa (n = 17). RESULTS: The antigen was aberrantly expressed in the antral mucosal epithelium in 11 of 12 cases (92%) with acute-on-chronic gastritis when H pylori was also present. It was present in the antrum in only seven of 18 H pylori negative cases (39%) with acute-on-chronic/chronic gastritis. One of three cases of acute gastritis and three of seven cases of chronic gastric erosions (non-inflamed category) showed positive staining. Generally, there was more staining in the antral than body mucosa and in the surface/foveolar epithelium than in the glands. No aberrant HLA-DR antigen expression was found in the 10 cases of normal gastric mucosa examined. CONCLUSIONS: These findings suggest that H pylori may have a role in the induction of class II HLA antigen expression in chronic gastritis and lend support to the view that these organisms may be responsible for part of the inflammatory response.

Expression of HLA-DR antigen in different histological types of gastric polyp.

AIMS: To study the expression of HLA-DR antigen in the different histological types of gastric polyps. METHODS: Ninety five cases of gastric polyps were histologically classified and examined for the presence of Helicobacter pylori, and for degree and type of inflammation. Further sections were stained immunohistochemically for HLA-DR antigen expression in the epithelium using a monoclonal antibody that was reactive to formalin-fixed paraffin wax embedded tissue. RESULTS: HLA-DR antigen was expressed in all of the inflammatory polyps studied (20/20), and in most hyperplastic (12/16) and adenomatous (4/6) polyps. Only a few fundic gland polyps (8/51) stained positively for HLA-DR antigen. Gastric polyps seem to have a greater tendency to express HLA-DR antigens than non-polypoid gastric mucosa, even after considering the factors that may affect HLA-DR antigen expression, such as inflammation and the presence of H pylori. CONCLUSIONS: Growth disturbances/polyp formation may be associated with increased HLA-DR antigen expression.

p53 expression in hepatocellular carcinoma in a population in Singapore with endemic hepatitis B virus infection.

AIMS: To study the expression and clinical significance (if any) of p53 protein in hepatocellular carcinomas (HCC) arising in a population with endemic hepatitis B virus (HBV) infection. METHODS: Immunohistochemical staining was performed on formalin fixed, paraffin was embedded histological sections of 46 HCC cases using an antihuman p53 monoclonal antibody; serial sections were also stained for hepatitis B surface antigen (HBsAg), hepatitis B core antigen (HBcAg) and alpha fetoprotein (AFP). Nuclear p53 staining was assessed according to intensity (absent, weak or strong) and extent (< 5%, 6-25%, 26-50%, and > 50%) of positive cells. Tissue HBsAg, HBcAg and AFP were recorded as absent or present. RESULTS: The p53 protein was expressed in 35% (16 of 46) of HCCs; the positive rate in grade III/IV tumours (13 of 31; 42%) was higher than in grade I/II tumours (three of 15; 20%) but this was not statistically significant. HBsAg positive tumours showed almost the same proportion of p53 staining (11 of 29; 38%) as HBsAg negative ones (five of 17; 29%). CONCLUSIONS: The p53 protein was expressed in 35% of HCC cases. There was no statistically significant correlation between HBV infection and p53 protein expression. Similarly, there was no definite correlation between p53 positivity and tumour size, histological grade or vascular invasion.

Lymphocytic gastritis-like T cell lymphoma: molecular evidence of an unusual recurrence.

This report describes a patient with a gastric biopsy specimen showing histomorphological and immunohistochemical appearances indistinguishable from those usually present in lymphocytic gastritis, a rare condition of unknown aetiology with a distinctive phenotype. The patient had a history of a biopsy confirmed T cell non-Hodgkin lymphoma at two anatomical sites (bladder and stomach), which was subsequently treated. Molecular analysis of the T cell receptor (TCR) gamma chain gene rearrangements showed a distinct monoclonal T cell population in the bladder and gastric biopsies. The same analysis in the lymphocytic gastritis-like biopsy sample showed a monoclonal population with identical base pair size to that identified in the other specimens. This report highlights the importance of TCR gene rearrangement analysis in the diagnosis of unusual gastric inflammation, and the use of capillary electrophoresis based polymerase chain reaction in the follow up of lymphoproliferative disorders.

Comparison of the structure-activity relationships of melatonin receptor agonists and antagonists: lengthening the N-acyl side-chain has differing effects on potency on Xenopus melanophores.

The potency and affinity of two series of melatonin receptor ligands were examined using the pigment aggregation response in a clonal line of Xenopus laevis melanophores and radioligand binding assays on native receptors in chicken brain, recombinant human mt1 and MT2 and Xenopus laevis mel1c receptor subtypes. One series was based on melatonin and had a methoxy group at the 5-position of the indole ring, while the other was based on luzindole and lacked this substituent but did have a 2-benzyl moiety; the N-acyl group of each series of analogues was varied from one to five carbon atoms. All analogues in the melatonin series were full agonists in melanophores (pEC50 7.76-10.24), while all compounds in the luzindole series were competitive melatonin antagonists (pA2 5.47-6.60). With the agonist series, increasing the N-acyl side-chain from one to three carbon atoms was well tolerated in both the functional and binding assays, but further lengthening of the side-chain progressively and dramatically reduced potency and affinity. In contrast, for the antagonist series neither potency nor binding affinity changed substantially with the length of the N-acyl chain, except at the recombinant MT2 subtype where two of the analogues had a lower affinity. In binding assays, three of the five antagonists were MT2-selective; the most selective analogue (N-pentanoyl 2-benzyltryptamine, MT2 pKi 8.03) having 89- and 229-fold higher affinity than at mt1 or mel1c receptor subtypes. The different structure-activity relationships of these receptor agonists and antagonists is discussed with regard to the possible binding sites of agonists and antagonists within the receptor protein.

An immunohistochemical study of p53 protein in the different histological subtypes of gastric carcinoma.

p53 mutations are known to occur frequently in human cancers, including gastric carcinomas. Previous studies of its incidence in gastric carcinomas had shown a varying incidence ranging from a low of 4% to as high as 57%. In this study, 42 cases of gastric carcinomas were analyzed for p53 using a commercially available mouse monoclonal antibody in routinely formalin-fixed paraffin-embedded tissue sections. These included 22 intestinal-type (7 well/moderately differentiated and 15 poorly differentiated), 16 diffuse-type and 4 mixed. Altogether, 60% of our cases stained positively for p53. Overall, well/moderately differentiated intestinal-type carcinomas stained more frequently for p53 than poorly differentiated intestinal-type carcinomas (p < 0.075). A comparison between the incidence in diffuse-type (69%) and intestinal type (55%) was unremarkable. p53 staining was also present in 3 of the 4 early cases studied. The results suggest that p53 mutations play an important role in carcinogenesis in gastric carcinoma and further implies that p53 mutation may be an early occurrence during tumor transformation.

An immunohistochemical study of p53 protein in ovarian mucinous neoplasms.

p53 gene mutations are among the most common genetic lesions in human cancers. While previous studies have established the presence of p53 protein in ovarian carcinomas some have not shown the alteration of the p53 gene to be a feature in benign or borderline ovarian epithelial neoplasms. In this study we examined both benign and borderline malignant/malignant mucinous neoplasms for p53 protein accumulation by the means of an anti-human p53 protein monoclonal antibody on paraffin sections. Our results show that p53 protein accumulation is associated to a similar degree with both malignant mucinous cystadenocarcinomas and mucinous cystademonas of borderline malignancy. This suggests that p53 mutations may play an important and early role in the malignant transformations of one-third or more of mucinous ovarian neoplasms. Furthermore, among the mucinous cystadenomas of borderline malignancy where p53 staining was present, staining could be found in the morphologically benign areas thus indicating that, despite their innocuous appearance, such epithelial cells might have already taken a very important step in their evolution to frank malignancy.