Analysis of gastrin-17 and its related influencing factors in physical examination results

BACKGROUND

To analyze the difference of serum gastrin-17 (G17) level in healthy people with different sex, age, and body mass index (BMI), to explore the correlation between G17 and pepsinogen, and to study the influences of Helicobacter pylori (H. pylori) infection and various inflammatory factors on G17 secretion level.

METHODS

A total of 531 subjects who received physical examination in our center from April 2019 to December 2019 were enrolled in the study. All subjects were tested for G17, pepsinogen I (PGI), pepsinogen II (PGII), PGI/PGII ratio (PGR), H. pylori, serum amyloid A (SAA), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). The difference of G17 secretion in different subjects and its correlation with PG were analyzed to investigate H. pylori infection and expound the effects of inflammatory indicators on G17.

RESULTS

There was no significant difference in G17 secretion level in people with different sex, age and BMI (p > .05). G17 positively correlated with PGI and PGII, but negatively correlated with PGR. The G17 level of H. pylori-positive subjects was 10.16 ± 12.84, and prominently higher than that of H. pylori-negative subjects (3.27 ± 6.65). SAA and H. pylori infection were the greater risk factors for G17 abnormality among various indicators. CRP and ESR had no effect on G17 abnormality.

CONCLUSIONS

G17 secretion is closely related to PG and H. pylori. Combined screening contributes to early screening of gastrointestinal diseases in normal people or groups at high risk for gastric cancer, but the influence of inflammatory indicators on G17 should be excluded to improve the reliability of the results.

Protective effect of the combination of essential oil from patchouli and tangerine peel against gastric ulcer in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Essential oil (EO) is the main extract of patchouli and tangerine peel with antiinflammatory, antiulcer, and other functions. However, the efficacy and mechanism of the combination of EO from patchouli and tangerine peel against gastric ulcer (GU) are unclear.

AIM OF THE STUDY

This study aims to reveal the protective effect of the combination of EO from patchouli and tangerine peel against GU in rats, as well as explore the optimal ratio and possible mechanism of EO in GU treatment.

MATERIALS AND METHODS

The GU model is executed via water immersion and restraint stress. The repair effect of EO in different proportions on gastric mucosa injury and the effects on serum gastrin (GAS), pepsinogen C (PGC), prostaglandin E2 (PGE2), and 5-hydroxytryptamine in GU rats were observed. The optimal ratio obtained was used in the second part to set different dose groups for further experiment. The effects of the different EO doses on gastric mucosal ulcer formation and gastric acid secretion were evaluated. The morphology of chief and parietal cells were observed via transmission electron microscopy. The contents of GAS, PGC, substance P (SP), cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), cholecystokinin (CCK), PGE2, and motilin (MTL) in serum in different groups were detected via enzyme-linked immunosorbent assay. Expressions of epidermal growth factor (EGF) and trefoil factor 2 (TFF2) protein in gastric tissues were detected via immunohistochemistry, and expressions of c-Jun N-terminal kinase (JNK), P53, Bcl-2-associated X protein (Bax), and Caspase-3 protein in gastric tissues were detected via western blotting.

RESULTS

The EO from patchouli and tangerine peel at 1:2 ratio of compatibility significantly improved gastric mucosal injury, decreased serum GAS and PGC contents, and increased the PGE2 level in serum (p < 0.05). The mixture of EO from patchouli and tangerine peel (Mix-EO) can reduce the formation of gastric mucosal ulcers, reduce gastric mucosal injury, improve the expansion of the endoplasmic reticulum of the chief cells, repair mitochondrial damage, and inhibit the secretion of gastric acid by parietal cells. Mix-EO at 300 mg/kg can reduce the expression of serum GAS, PGC, SP, CCK, and cAMP/cGMP (p < 0.05 or 0.01); increase the expression of EGF and TFF2 protein in gastric tissues (p < 0.01); and inhibit the expression of JNK, p53, Bax, and Caspase-3 proteins (p < 0.01).

CONCLUSION

The combination of EO from patchouli and tangerine peel can repair the gastric mucosal damage in GU rats and prevent the occurrence of ulcers by inhibiting the secretion of gastric acid, enhancing the defensive ability of gastric mucosa, and suppressing the apoptosis of gastric epithelial cells. Moreover, the optimal compatible ratio of patchouli and tangerine peel is 1:2.

Induction of Gastric Cancer by Successive Oncogenic Activation in the Corpus

BACKGROUND & AIMS

Metaplasia and dysplasia in the corpus are reportedly derived from de-differentiation of chief cells. However, the cellular origin of metaplasia and cancer remained uncertain. Therefore, we investigated whether pepsinogen C (PGC) transcript-expressing cells represent the cellular origin of metaplasia and cancer using a novel Pgc-specific CreERT2 recombinase mouse model.

METHODS

We generated a Pgc-mCherry-IRES-CreERT2 (Pgc-CreERT2) knock-in mouse model. Pgc-CreERT2/+ and Rosa-EYFP mice were crossed to generate Pgc-CreERT2/Rosa-EYFP (Pgc-CreERT2/YFP) mice. Gastric tissues were collected, followed by lineage-tracing experiments and histologic and immunofluorescence staining. We further established Pgc-CreERT2;KrasG12D/+ mice and investigated whether PGC transcript-expressing cells are responsible for the precancerous state in gastric glands. To investigate cancer development from PGC transcript-expressing cells with activated Kras, inactivated Apc, and Trp53 signaling pathways, we crossed Pgc-CreERT2/+ mice with conditional KrasG12D, Apcflox, Trp53flox mice.

RESULTS

Expectedly, mCherry mainly labeled chief cells in the Pgc-CreERT2 mice. However, mCherry was also detected throughout the neck cell and isthmal stem/progenitor regions, albeit at lower levels. In the Pgc-CreERT2;KrasG12D/+ mice, PGC transcript-expressing cells with KrasG12D/+ mutation presented pseudopyloric metaplasia. The early induction of proliferation at the isthmus may reflect the ability of isthmal progenitors to react rapidly to Pgc-driven KrasG12D/+ oncogenic mutation. Furthermore, Pgc-CreERT2;KrasG12D/+;Apcflox/flox mice presented intramucosal dysplasia/carcinoma and Pgc-CreERT2;KrasG12D/+;Apcflox/flox;Trp53flox/flox mice presented invasive and metastatic gastric carcinoma.

CONCLUSIONS

The Pgc-CreERT2 knock-in mouse is an invaluable tool to study the effects of successive oncogenic activation in the mouse corpus. Time-course observations can be made regarding the responses of isthmal and chief cells to oncogenic insults. We can observe stomach-specific tumorigenesis from the beginning to metastatic development.

A retrospective study assessing the acceleration effect of type I Helicobacter pylori infection on the progress of atrophic gastritis

Based on the antibody typing classification, Helicobacter pylori infection can be divided into type I H. pylori infection and type II H. pylori infection. To observe the effects of different H. pylori infection types on the distribution of histopathological characteristics and the levels of three items of serum gastric function (PG I, PG II, G-17). 1175 cases from October 2018 to February 2020 were collected with ratio 1:2. All patients were performed with ¹⁴C-Urea breath test (¹⁴C-UBT), H. pylori antibody typing classification, three items of serum gastric function detection, painless gastroscopy, pathological examination, etc. According to H. pylori antibody typing classification, patients were divided into three groups: type I H. pylori infection group, type II H. pylori infection group and control group. Significant difference existed among type I H. pylori infection group, type II H. pylori infection group and control group in inflammation and activity (χ² = 165.43, 354.88, P all < 0.01). The proportion of three groups in OLGA staging had statistic difference (χ² = 67.99, P all < 0.01); Compared with type II H. pylori infection group and control group, the level of pepsinogen I, pepsinogen II, gastrin17 in type I H. pylori infection group increased, and PG I/PG II ratio (PG I/PG II ratio, PGR) decreased, which was statistically significant (χ² = 35.08, 166.24, 134.21, 141.19; P all < 0.01). Type I H. pylori infection worsened the severity of gastric mucosal inflammation and activity. H. pylori infection was prone to induce atrophy of gastric mucosa, while type I H. pylori infection played a key role in promoting the progress of atrophic gastritis and affected the level of serum gastric function. The study indicated that the eradication of H. pylori should be treated individually.

SNP interactions of PGC with its neighbor lncRNAs enhance the susceptibility to gastric cancer/atrophic gastritis and influence the expression of involved molecules

Multidimensional interactions of multiple factors are more important in promoting cancer initiation. Gene-gene interactions between protein-coding genes have been paid great attention, while rare studies refer to the interactions between encoding and noncoding genes. Our research group previously found encoding gene PGC polymorphisms could affect the susceptibility to atrophic gastritis (AG) and gastric cancer (GC). Interestingly, several SNPs in long noncoding RNA (lncRNA) genes, just adjacent to PGC, were found to be associated with AG risk and GC prognosis afterward. This study aims to explore the SNP interactions between PGC and its neighbor lncRNAs on the risk of AG and GC. Genotyping for seven PGC SNPs and seven lncRNA SNPs was conducted using Sequenom MassARRAY platform in a total of 2228 northern Chinese subjects, including 536 GC cases, 810 AG cases, and 882 controls. We found 15 pairwise PGC-lncRNAs SNPs had interactions: Five pairs were associated with AG risk, and ten pairs were associated with GC risk. Moreover, two GC-related interactions PGC rs6939861 with lnc-C6orf-132-1 rs7749023 and rs7747696 survived the Bonferroni correction (P_correction  = 0.049 and 0.007, respectively). Several combinations showed obvious epistasis and cumulative effects on disease risk. Some three-way interactions of SNPs with smoking and drinking could also be observed. Besides, a few interacting SNPs showed correlations with the expression levels of PGC protein and related lncRNAs in serum. Our study would provide research clues for further screening combination biomarkers uniting both protein-coding and noncoding genes with the potential in prediction of the susceptibility to GC and its precursor.

Expression and Clinical Significance of Pepsinogen C in Resectable Pancreatic Cancer

Pepsinogen C is an aspartyl-proteinase usually involved in the digestion of proteins in the stomach, and an androgen- inducible protein in breast cancer cells. In this study we evaluated its expression and clinical significance in patients with resectable pancreatic cancer. Pepsinogen C expression was examined by immunohistochemical methods in a series of 73 pancreatic carcinomas. The prognostic value of pepsinogen C was retrospectively evaluated by multivariate analysis. A total of 21 (28.8%) pancreatic carcinomas stained positively for pepsinogen C. The percentage of pepsinogen C-positive tumors was significantly higher in well-differentiated tumors (38.3%) than in moderately differentiated (15.8%) and poorly differentiated (0%) tumors (p<0.05). In addition, statistical analysis revealed that pepsinogen C expression was associated with clinical outcome. Thus, patients with pepsinogen C-negative tumors have a poorer overall survival than those with pepsinogen C-positive tumors. Our results led us to consider that the expression of pepsinogen C may represent a useful biological marker in pancreatic cancer. Expression of this protein may be a marker of gastric-type differentiation of the tumors and it might also reflect the existence of a complete hormone receptor pathway in a subset of pancreatic carcinomas.

Atrophic and Metaplastic Progression in the Background Mucosa of Patients with Gastric Adenoma

BACKGROUND

In patients with adenoma, assessing premalignant changes in the surrounding mucosa is important for surveillance. This study evaluated atrophic and metaplastic progression in the background mucosa of adenoma or early gastric cancer (EGC) cases.

METHODS

Among 146 consecutive patients who underwent endoscopic resection for intestinal-type gastric neoplasia, the adenoma group included 56 patients with low-grade dysplasia and the ECG group included 90 patients with high-grade dysplasia or invasive carcinoma. For histology, 3 paired biopsies were obtained from the antrum, corpus lesser curvature (CLC), and corpus greater curvature (CGC). Serological atrophy was determined based on pepsinogen A (PGA), progastricsin (PGC), gastrin-17, and total ghrelin levels. Topographic progression of atrophy and/or metaplasia was staged using the operative link on gastritis assessment (OLGA) and operative link on gastric intestinal metaplasia assessment (OLGIM) systems.

RESULTS

Rates of moderate-to-marked histological atrophy/metaplasia in patients with adenoma were 52.7%/78.2% at the antrum (vs. 58.8%/76.4% in EGC group), 63.5%/75.0% at the CLC (vs. 60.2%/69.7% in EGC group), and 10.9%/17.9% at the CGC (vs. 5.6%/7.8% in EGC group). Serological atrophy indicated by PGA and PGC occurred in 23.2% and 15.6% of cases in the adenoma and ECG groups, respectively (p = 0.25). Mean serum gastrin-17 concentrations of the adenoma group and EGC group were 10.4 and 9.0 pmol/L, respectively (p = 0.54). Mean serum total ghrelin levels were 216.6 and 209.5 pg/mL, respectively (p = 0.71). Additionally, between group rates of stage III-IV OLGA and OLGIM were similar (25.9% vs. 25.0%, p = 0.90; 41.8% vs. 44.9%, p = 0.71, respectively).

CONCLUSIONS

Atrophic and metaplastic progression is extensive and severe in gastric adenoma patients. A surveillance strategy for metachronous tumors should be applied similarly for patients with adenoma or EGC.

[The clinical significance of GastroPanel in diagnostics of Helicobacter pylori eradication efficiency in patients with dyspepsia with correlation of family history of gastric cancer]

Gastric cancer remains a significant medical and social problem. Familial, hereditary, social, and demographic factors increase the susceptibility of subjects to cancer development, especially those infected with Helicobacter pylori (H. pylori). Apart from genetic studies, there are ongoing biochemical studies of possible practical value in assessment of the risk of gastric cancer development. The GastroPanelBiohit test, that include determination of the levels of gastrin (G-17), pepsinogen I (PGI), pepsinogen II (PGII) and antibodies IgG/IgA against H. pylori in serum, allowed us to determine whether there are any abnormal changes in the gastric mucosa. The aim of the study was to determine whether GastroPanel parameters, identified in patients with dyspeptic symptoms (with or without history of gastric cancer in first degree relatives) before and after successful eradication of H. pylori, have any clinical value, especially in gastric cancer development.

MATERIAL AND METHODS

The study comprised 61 patients aged 18-56 years with symptoms of dyspepsia. In all patients, the preliminary urea breath test (UBT) for the presence of H. pylori was performed and the positive result qualified for further study. For final analysis, 42 patients were approved, who were divided into two groups: group I (a control group) - 22 patients with negative family history of gastric cancer among the relatives of first degree, group II - 20 patients with positive history of gastric cancer among the relatives of first degree. All the patients had the gastroscopy with the biopsy of gastric mucosa for the histopathological evaluation. Additionally, the GastroPanel test was performed.

RESULTS

In the blood serum of the patients with H. pylori infection, the concentrations of gastrin (G-17), pepsinogen I (PGI) and pepsinogen II (PGII) did not depend on family history of gastric cancer (p > 0.05). Successful eradication of H. pylori decreases the levels of G-17, PGI and PGII (statistical significance p < 0.05), and this correlates with the histopathological changes of gastric mucosa. The patients with positive family history of gastric cancer had more intense H. pylori colonization of gastric mucosa (IV degree of insensitivity of infection in UBT; group I - 22% vs group II - 69%) as compared to the control group. After effective eradication of H. pylori, statistically significant decreases of IgG H. pylori antibodies and of the level of gastrin (p < 0.05) in blood serum were seen (in a 3 months follow up) only in the control group.

CONCLUSIONS

Independently of the history of familial gastric cancer, the GastroPanelBiohit test provides important clinical data useful for diagnosis, for assessment of effectiveness of H. pylori eradication therapy and in evaluation of the degree of the inflammatory changes in gastric mucosa.

H. pylori CagL-Y58/E59 prime higher integrin α5β1 in adverse pH condition to enhance hypochlorhydria vicious cycle for gastric carcinogenesis

Background/Aims

H. pylori CagL amino acid polymorphisms such as Y58/E59 can increase integrin α5β1 expression and gastric cancer risk. Hypochlorhydria during chronic H. pylori infection promotes gastric carcinogenesis. The study test whether CagL-Y58/E59 isolates may regulate integrin α5β1 to translocate CagA via the type IV secretory system even under adverse pH conditions, and whether the integrin α5β1 expression primed by H. pylori is a pH-dependent process involving hypochlorhydria in a vicious cycle to promote gastric carcinogenesis.

Methods

The expressions of integrin α5 and β1, CagA phosphorylation, IL-8, FAK, EGFR, and AKT activation of AGS cells exposed to CagL-Y58/E59 H. pylori, isogenic mutants, and different H. pylori CagL amino acid replacement mutants under different pH values were determined. Differences in the pepsinogen I/II ratio (indirectly indicating gastric acidity) and gastric integrin α5β1 expression were compared among the 172 H. pylori-infected patients with different cancer risks.

Results

Even under adversely low pH condition, H. pylori CagL-Y58/E59 still keep active integrin β1 with stronger binding affinity, CagA translocation, IL-8, FAK, EGFR, and AKT activation than the other mutants (p<0.05). The in vitro assay revealed higher priming of integrin α5β1 by H. pylori under elevated pH as hypochlorhydria (p<0.05). In the H. pylori-infected patients, the gastric integrin α5β1 expressions were higher in those with pepsinogen I/II ratio <6 than in those without (p<0.05).

Conclusions

H. pylori CagL-Y58/E59 prime higher integrin under adverse pH and may involve to enhance hypochlorhydria vicious cycle for gastric carcinogenesis, and thus require an early eradication.

[Restoration of secretory activity of digestive glands in conditions of acute hyperkinesis at persons with different levels of motor activity]

The dynamics' features of restoration reactions of the secretory function of gastric glands have been studied at patients with differences in the level and specificity of daily physical activity. The dependence between the level and characteristics of daily physical activity and reactivity of the secretory apparatus of the gastric glands in the recovery period after the muscle load has been established. The high reactivity of the secretory activity of digestive glands is typical for individuals with high level of daily physical activity. The differences of the functional stability of the secretion's mechanisms of various components of gastric juice under the influence of physical exercise and in recovery have been revealed. The greatest stability of the secretory mechanisms of digestive glands has been discovered at athletes practicing with the development of endurance--at skiers. Heterochronous reducing reactions of gastric and pancreatic secretion after physical stress have been defined. The reduction of secretion's mechanisms of gastric juice ingredients and the electrolyte and acid composition of digestive juices isn't simultaneous: the first order is for ferment's secretion. The inverse relationship between the content of digestive enzymes pepsinogen-1 and -2 in blood's serum and the concentration of proteolytic enzymes in the gastric content has been found at persons with various degrees of adaptation to the muscular tension.

The Rho pathway mediates transition to an alveolar type I cell phenotype during static stretch of alveolar type II cells

Stretch is an essential mechanism for lung growth and development. Animal models in which fetal lungs have been chronically over or underdistended demonstrate a disrupted mix of type II and type I cells, with static overdistention typically promoting a type I cell phenotype. The Rho GTPase family, key regulators of cytoskeletal signaling, are known to mediate cellular differentiation in response to stretch in other organs. Using a well-described model of alveolar epithelial cell differentiation and a validated stretch device, we investigated the effects of supraphysiologic stretch on human fetal lung alveolar epithelial cell phenotype. Static stretch applied to epithelial cells suppressed type II cell markers (SP-B and Pepsinogen C, PGC), and induced type I cell markers (Caveolin-1, Claudin 7 and Plasminogen Activator Inhibitor-1, PAI-1) as predicted. Static stretch was also associated with Rho A activation. Furthermore, the Rho kinase inhibitor Y27632 decreased Rho A activation and blunted the stretch-induced changes in alveolar epithelial cell marker expression. Together these data provide further evidence that mechanical stimulation of the cytoskeleton and Rho activation are key upstream events in mechanotransduction-associated alveolar epithelial cell differentiation.

[Clinical and laboratory evaluation of efficiency of Helicobacter pylori eradication]

AIM

To assess the efficiency of eradication therapy in long-term period using the main signs of functional activity of gastric mucosa (gastrin-17, pepsinogen I, pepsinogen II) and serum antibodies to H. pylori.

MATERIALS AND METHODS

113 patients with chronic gastritis were examihed using clinical, endoscopic and laboratory-based methods of investigation, including GastroPanel Biohit, Finland.

RESULTS

It was observed that after 12 month of successful eradication therapy the titer of IgG to H. pylori did not exceed 60 IU/l, with pepsinogen I and pepsinogen II cut-off values set under 150 microg/l and 15 microg/l respectively.

CONCLUSION

The decrease of the titer of IgG to H. pylori and concentrations of pepsinogen I and II can be used as criteria of successful eradication therapy in long-term period.

[Correlation of pepsinogen C (PGC) gene insertion/deletion polymorphism to PGC protein expression in gastric mucosa and serum]

BACKGROUND AND OBJECTIVE

Human pepsinogen C (PGC) is an aspartic protease synthesized in gastric mucosa. PGC gene insertion/deletion polymorphism, which is located between exon 7 and 8, has been found to associate with gastric cancer (GC) susceptibility. This study was to investigate the relationship between PGC polymorphism with protein expression of PGC in gastric mucosa and serum.

METHODS

PGC insertion/deletion polymorphism was evaluated by PCR, followed by direct DNA sequencing in 493 cases of GC, atrophic gastritis (AG), gastric erosion ulcer (GEU) and superficial gastritis (SG). PGC protein expression in gastric mucosa was measured by immunohistochemistry. The serum PGC level was determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

In accordance with the following order SG-->GEU-->GA-->GC, the frequency of PGC homozygous allele 1 was gradually increased, which was higher in GC than in SG (P=0.018); while the protein expression of PGC in gastric mucosa was gradually decreased (P<0.01), along with a gradual decrease in the strong positive rate of PGC (P<0.05) except for SG vs. GEU. The serum level of PGC was significantly lower in SG than in GU(P=0.000) and GC(P=0.000). The frequency of PGC homozygous allele 1 was negatively correlated to PGC protein expression in gastric mucosa (r=-0.1085, P=0.023). From homozygous allele 1 to heterozygous allele 1, and to other genotypes, the PGC positive rate was gradually increased in gastric mucosa, with significant differences between homozygous allele 1 and other genotypes (P=0.009); while the strong-positive rate of PGC was gradually decreased only in SG group (P=0.047).

CONCLUSION

PGC gene insertion/deletion polymorphism is negatively related to PGC protein expression in gastric mucosa, but is not related to the serum PGC level.

Epidemiology of chronic atrophic gastritis: population-based study among 9444 older adults from Germany

BACKGROUND

Epidemiological data on chronic atrophic gastritis from general population samples are sparse in Germany.

AIM

To assess prevalence of chronic atrophic gastritis according to potential risk factors and clinical outcomes in a large-scale population-based study.

METHODS

In the baseline examination of ESTHER, a population-based cohort study conducted in Germany, serological measurements of pepsinogen (PG) I and II and Helicobacter pylori antibodies were taken in 9444 women and men aged 50-74 years. Information on potential risk factors and medical history were obtained by questionnaire.

RESULTS

With the definition used in the EUROGAST study (PG I < 25 ng/mL), prevalence of chronic atrophic gastritis increased from 4.8% in age group 50-54 to 8.7% in age group 70-74. An alternative definition of chronic atrophic gastritis (PG I < 70 ng/mL and PG I/PG II < 3), used in multiple studies from Japan, revealed a greater increase with age (from 2.7% to 9.1%) and a strong association with H. pylori infection (adjusted odds ratio: 2.9, 95% confidence interval: 2.4-3.7). With both definitions, a strong inverse association with heartburn was observed.

CONCLUSIONS

Overall chronic atrophic gastritis prevalence is low among older adults in Germany, but it strongly increases with age and H. pylori infection.

Expression of androgen receptor and two androgen-induced proteins (apolipoprotein D and pepsinogen C) in ductal carcinoma in situ of the breast

AIMS

To evaluate the expression of androgen receptors (AR) and two androgen-induced proteins [apolipoprotein D (ApoD) and pepsinogen C (PepC)] in ductal carcinoma in situ (DCIS) of the breast.

METHODS AND RESULTS

AR, ApoD and PepC expression was examined in 28 cases of pure DCIS and in 31 cases of DCIS adjacent to invasive carcinoma of the breast using immunohistochemical methods and then correlated with the architectural subtype, the degree of differentiation and the ostrogen receptor (ER)/progesterone receptor (PgR)/HER-2 status. We found no significant differences between pure DCIS and DCIS adjacent to invasive breast cancer regarding the percentage of positive cases for ApoD (64.3% versus 54.8%), PepC (42.9% versus 48.4%), ER (64.3% versus 58.1%), PgR (60.7% versus 58.1%) and HER-2 (39.3% versus 67.7%). However, there was a significantly higher percentage of AR+ DCIS among those adjacent to invasive carcinomas of the breast than among pure DCIS lesions (93.5% versus 60.9%) (P = 0.009). AR expression did not correlate with architectural subtype, degree of differentiation, or ER/PgR/HER-2/ApoD/PepC status, in cases of pure DCIS, nor in DCIS adjacent to invasive carcinoma of the breast.

CONCLUSIONS

AR expression may represent an independent predictive factor in DCIS of the breast.

Low- and high-grade non-invasive gastric neoplasia (formerly dysplasia): cytological differentiation (gastro-entero-pancreatic antigens) in association with p53 pattern expression

BACKGROUND/AIMS

In order to better define the evolutive potentiality of non-invasive neoplasia (formerly dysplasia) a study of the cytological differentiation and of the behavior of p53 in relation to the clinical progress has been performed.

METHODOLOGY

Gastro-entero-pancreatic antigens, p53 and Ki-67 expression were evaluated in 120 cases of epithelial gastric dysplasia: 70 cases of low-grade dysplasia (LGD) and 50 cases of high-grade dysplasia (HGD). For the cytological study four antigens were studied: two of them gastric (pepsinogen C, gastric foveolar M1), one enteric (CAR-5) and one pancreatic (DU-PAN-2). Routinely processed tissue sections of a colon carcinoma known to contain mutant p53 were used as positive controls for p53 immunohistochemistry. For Ki-67 immunohistochemistry, routinely processed tissue sections of normal lymph node and tonsil were used as staining controls.

RESULTS

The study of the coexpression of the gastro-entero-pancreatic antigens showed how all cases of non-invasive neoplasia associated with or progressed to gastric carcinoma (GC) were characterized by entero-pancreatic markers and, in particular, in case of LGD p53 expression positivity was evidenced in 66.6% of cases. Ki-67 hyperproliferation is present in 100% of cases.

CONCLUSIONS

The cytological study, only if confirmed by wider casuistries, could represent further information in order to better define the follow-up and the therapeutical decisions in case of non-invasive gastric neoplasia therefore, the immunophenotypic study in association with p53 could lead to more personalized therapeutical choices.

Influence of aging, gastric mucosal atrophy and dietary habits on gastric secretion

BACKGROUND/AIMS

Studies in Japan have reported on the association between gastric secretion and age with consideration given to gastric mucosal atrophy but not pepsin secretion. Though recent reports have shown enhanced gastric secretion in the Japanese, attributed to dietary westernization, the association between diet and gastric secretion is not clear. In this study, the association between gastric secretion and mucosal atrophy, age, and dietary habits was evaluated.

METHODOLOGY

The subjects were 47 preoperative patients without upper gastrointestinal disorders. Acid secretion, pepsin secretion, serum pepsinogen level, and serum Helicobacter pylori antibody titer were measured. Dietary habits were investigated by questionnaire.

RESULTS

Gastric secretion did not differ among the young, middle, and elderly age groups. Compared with the group without atrophy (pepsinogen I/II > 3.0, 32 subjects), the group with atrophy (I/II < or = 2.5, 11 subjects) showed significantly decreased gastric secretion and a significantly high Helicobacter pyloriseropositive rate. In the group without atrophy, acid and pepsin secretion was significantly correlated with energy intake, pepsin secretion was significantly correlated with glucose intake, and gastric secretion tended to increase with age.

CONCLUSIONS

In the absence of gastric mucosal atrophy, gastric secretion does not decrease with age, and is related to dietary habits.

The relation of pepsinogen group II (PGII) expression to intestinal metaplasia and gastric cancer

AIMS

A substantial minority of intestinal metaplasia (IM)-associated stomach cancers express a gastric product-pepsinogen group II (PGII). The aim of this study was to examine PGII expression as it relates to IM and to tumour heterogeneity.

METHODS AND RESULTS

The extent of IM was divided into four levels: none, minimal, moderate, extensive. Stomach specimens (N = 165) were stained for PGII and two tumour markers, epidermal growth factor receptor (EGFr) and p53. PGII was more likely to be expressed with moderate or extensive IM than with minimal or no IM (P = 0.05). Cancers that expressed PGII were more likely to be of high stage than those that did not (P = 0.035). Of 25 cases that expressed all three markers (PGII, EGFr, p53), 20 (80%) had stage 3 or 4 disease, compared with 11 (37%) advanced cancers expressing none of the markers (P = 0.001). Cancers expressing one or two markers were between these extremes.

CONCLUSIONS

PGII+ cancers in IM-associated gastric cancers may derive from residual gastric glands, or may arise from postinduction reversion to a gastric phenotype from intestinalized cells. This is supported by the more frequent association of PGII expression with the most extensive degrees of IM and its association with high-stage cancers that display heterogeneity in tumour marker expression.

[Gene expression profiling of diffuse-type gastric cancer by cDNA microarray]

OBJECTIVE

To identify cancer-related genes in diffuse-type gastric cancer and to explore its molecular mechanism by cDNA microarray analysis.

METHODS

A total of 22 pairs of diffuse-type gastric cancer tissue and the corresponding normal mucosa were taken and freshly frozen. cDNA microarray with 14,592 genes/ESTs was used. Genes were considered to be up- or down-regulated when the fluorescent intensity ratio between tumor and normal mucosa was over 2-fold in over 50% of the samples (P < 0.05). Hierarchical clustering of regulated genes was performed as a measure to study expressional similarity. Validation of array results was carried out by real time quantitative PCR (QPCR).

RESULTS

Compared with those of corresponding normal mucosa, there were a total of 153 genes/ESTs up-regulated and 204 down-regulated in diffuse-type gastric cancer. Hierarchical clustering demonstrated that the genes belonging to the same subgroup displayed similar function. Most of the overexpressed genes were those related to cell adhesion, cell motility, matrix reconstruction, cell proliferation and/or signal transduction; while genes related to defense response, toxicoid metabolism, DNA repairing, nuclear-cytoplasmic transport and/or anti-apoptosis made up the main list of the underexpressed genes. Seven genes showed higher expression in TNM (T I + T II) group than in (T III + T IV) group. QPCR confirmed the array analysis results.

CONCLUSION

Gene expression profiling by cDNA microarray analysis provides not only molecular understanding of biological properties of cancer, but may also be helpful in discovering new diagnostic markers and therapeutic targets in gastric adenocarcinoma.

Dynamic expression of pepsinogen C in gastric cancer, precancerous lesions and Helicobacter pylori associated gastric diseases

AIM

To investigate the relationship between the expression of pepsinogen C (PGC) and gastric cancer, precancerous diseases, and Helicobacter pylori (H pylori) infection.

METHODS

The expression of PGC was determined by immunohistochemistry method in 430 cases of gastric mucosa. H pylori infection was determined by HE staining, PCR and ELISA in 318 specimens.

RESULTS

The positive rate of PGC expression in 54 cases of normal gastric mucosa was 100%. The positive rates of PGC expression in superficial gastritis or gastric ulcer or erosion, atrophic gastritis or gastric dysplasia and gastric cancer decreased significantly in sequence (P<0.05; 100%/89.2% vs 14.3%/15.2% vs 2.4%). The over-expression rate of PGC in group of superficial gastritis with H pylori infection was higher than that in group without H pylori infection (P<0.05; chi2= 0.032 28/33 vs 15/25). The positive rate of PGC expression in group of atrophic gastritis with H pylori infection was lower than that in group without H pylori infection (P<0.01; chi2= 0.003 4/61 vs 9/30), and in dysplasia and gastric cancer.

CONCLUSION

The level of PGC expression has a close relationship with the degree of malignancy of gastric mucosa and development of gastric lesions. There is a relationship between H pylori infection and expression of antigen PGC in gastric mucosa, the positive rate of PGC expression increases in early stage of gastric lesions with H pylori infection such as gastric inflammation and decreases during the late stage such as precancerous diseases and gastric cancer. PGC-negative cases with H pylori-positive gastric lesions should be given special attention.

Pepsinogen C expression in intestinal IEC-6 cells

Pepsinogen C (PGC) is the inactive precursor of pepsin C, which is a member of the aspartic proteinase family of proteolytic enzymes, and is found within the vertebrate stomach. The precursor molecule is synthesised within the gastric epithelial cells and secreted into the gastric lumen where it undergoes an autocatalytic activation under acidic conditions to the proteolytic molecule. However, the synthesis of PGC has also been reported in numerous non-gastric tissues including the prostate gland and the Brunner's gland of the small intestine. The physiological significance of PGC in these tissues is not known and studies are limited by the lack of appropriate in vitro cell models. We report here the use of the rat intestinal cell line, IEC-6, as an in vitro model to study the role of pepsinogen C in the intestine. PGC expression was detected in the IEC-6 cells by RT-PCR and immunocytochemistry, using a PGC specific antibody, localised the protein to cytoplasmic secretory granules. Enzymatic assay confirmed the presence of a functional protein exhibiting pepsin activity. Using semi-quantitative RT-PCR we showed that PGC gene expression was up-regulated by the gastro-intestinal hormones gastrin and secretin, and forskolin which stimulates adenylate cyclase activity. This study demonstrates that the IEC-6 cells provide a unique in vitro model for studying pepsinogen C and its potential role(s) in the small intestine.

Expression and clinical significance of pepsinogen C in uveal melanomas

PURPOSE

we investigated by immunohistochemistry the pepsinogen C (pepC) expression in uveal melanomas and analyzed the possible relationship to clinicopathological parameters and prognostic significance.

METHODS

We studied 22 patients who had undergone enucleation of the eyeball or local tumor resection for uveal melanoma. The specimens were immunostained for pepC on formalin-fixed, paraffin-embedded sections. Sex, age, tumor location, histological type, local invasion, postoperative treatment and metastasis were evaluated.

RESULTS

Eleven tumors (50%) were positive for pepsinogen C. The percentage of pepC-positive tumors was significantly higher in uveal melanomas with scleral invasion than in those without scleral invasion (p < 0.01). PepC expression was significantly associated with a shortened overall survival (p < 0.05).

CONCLUSIONS

Our results show that pepsinogen C may be expressed by uveal melanoma and suggest that this protein could be considered as a new, unfavorable prognostic factor in these tumors.

Expression of two androgen-induced proteins (pepsinogen C and apolipoprotein d) in epithelial skin cancers of the eyelids

By immunohistochemistry, we investigated pepsinogen C (pepC) and apolipoprotein D (apoD) expressions in 23 basal cell (BCC) and 25 squamous cell carcinomas (SCC) of the eyelids and analyzed the possible relationship to clinicopathological parameters. A total of 3 (13%) BCC and 7 (28%) SCC stained positively for pepC, whereas 11 (47.8%) BCC and 6 (24%) SCC stained positively for apoD. No significant correlation was found between pepC and apoD expressions and patients or tumor characteristics (p > 0.05). pepC and apoD, two androgen-inducible proteins, may be expressed by BCC and SCC of the eyelids. Further studies will be necessary to determine their clinical significance.

Pepsinogen C: a type 2 cell-specific protease

Pepsinogen C, also known as progastricsin or pepsinogen II, is an aspartic protease expressed primarily in gastric chief cells. Prior microarray studies of an in vitro model of type 2 cell differentiation indicated that pepsinogen C RNA was highly induced, comparable to surfactant protein RNA induction. Using second-trimester human fetal lung, third-trimester postnatal and adult lung, and a model of type 2 cell differentiation, we examined the specificity of pepsinogen C expression in lung. Pepsinogen C RNA and protein were only detected in >22 wk gestation samples of neonatal lung or in adult lung tissue. By immunohistochemistry and in situ hybridization, pepsinogen C expression was restricted to type 2 cells. Pepsinogen C expression was rapidly induced during type 2 cell differentiation and rapidly quenched with dedifferentiation of type 2 cells after withdrawal of hormones. In all samples, pepsinogen C expression occurred concomitantly with or in advance of processing of surfactant protein-B to its mature 8-kDa form. Our results indicate that pepsinogen C is a type 2 cell-specific marker that exhibits tight developmental regulation in vivo during human lung development, as well as during in vitro differentiation and dedifferentiation of type 2 cells.

Comparative study of two androgen-induced markers (apolipoprotein D and pepsinogen C) in female and male breast carcinoma

BACKGROUND

Male breast cancer (MBC) is a rare tumor in comparison to the same disease in the female population (FBC). Classical prognostic factors (tumor size, node status, estrogen receptor positivity, histological grade) have a similar prognostic value in both tumors, but MBC seems to have a worse outcome. Several markers under estrogen control have been shown with a similar incidence in breast tumors of both sexes, while androgen-induced markers have been detected in a higher percentage of breast tumors in males.

AIMS AND METHODS

Our purpose was to compare in 68 MBC and in 68 FBC the expression of Pepsinogen C (Pep C) and Apolipoprotein D (Apo D), two proteins under androgen control, by immunohistochemical methods.

RESULTS

Pep C was expressed by 52 of 68 (76.4%) MBC patients, whereas 34 of 68 (50%) FBC showed positive staining. Apo D was expressed by 57 of 68 (83.8%) MBC patients, while 40 of 68 (41.2%) FBC stained positively. Differences between percentages of positive expression were significant (p<0.005 for Pep C; p<0.0001 for Apo D). Moreover, differences between expression levels of Pep C and Apo D in both populations of patients were significant. The mean value of Pep C was significantly higher in male breast tumors (HSCORE = 141.3) than in the females (HSCORE = 80.3) (p<0.0001). Similarly, Apo D mean value was significantly higher in MBC (HSCORE = 161.5) than in FBC (HSCORE = 102.3) (p=0.006).

CONCLUSION

These differences can open the field of a more selective hormonal therapy that should not be based on estrogen receptor status only, but also on androgen receptor status.

Pepsinogen A, pepsinogen C, and gastrin as markers of atrophic chronic gastritis in European dyspeptics

Serum levels of pepsinogen and gastrin are parameters that can be used as biomarkers for gastric mucosa. The aim of this study was to validate these serum biomarkers, that is pepsinogen A (PGA), pepsinogen C (PGC), PGA/PGC ratio, and gastrin, as screening tests for precancerous lesions: atrophic chronic gastritis (ACG) or Helicobacter pylori-related corpus-predominant or multifocal atrophy. The study population was comprised of a subsample of 284 patients from the 451 included in the Eurohepygast cohort, between 1995 and 1997. The concentrations of PGA, PGC, and gastrin were measured by radioimmunoassays. Histological diagnosis was the gold standard. Cut-off points were calculated using receiving operator characteristics (ROC) curves. Factors linked to variation of biomarkers were identified using multivariate linear regression. The mean of each biomarker in the sample was: PGA, 77.4 microg x l(-1); PGC, 13.2 microg x l(-1); PGA/PGC, 6.7; and gastrin, 62.4 ng x l(-1). For ACG patients, the areas under the PGA, PGC, PGA/PGC, and gastrin ROC curves were 0.55, 0.62, 0.73, and 0.58, respectively. The best cut-off point for PGA/PGC was 5.6, with sensitivity 65% and specificity 77.9%. For H. pylori-related corpus-predominant or multifocal atrophy, the areas under the respective ROC curves were 0.57, 0.67, 0.84, and 0.69. The best cut-off point for PGA/PGC was 4.7, with sensitivity 77.1% and specificity 87.4%. The results suggested that only the PGA/PGC ratio can be considered as a biomarker for precancerous lesions of the stomach, and may be useful as a screening test.

Expression and clinical significance of pepsinogen C in epithelial ovarian carcinomas

BACKGROUND

Pepsinogen C (pep C) is a gastric aspartic protease of which is associated with a favorable prognosis in breast cancer. Recently, it has been demonstrated in other tumors of extradigestive origin.

STUDY DESIGN

We have analyzed pep C expression in 72 epithelial ovarian carcinomas by immunohistochemistry.

RESULTS

Nineteen (26%) tumors stained positively for pep C. Overall this expression was not associated with the clinicopathologic characteristics or with outcome. However, in patients with serum levels of CA 125 less than 35 U/ml, pep C expression identified a group with a more favorable prognosis.

CONCLUSION

Pepsinogen C is expressed in a quarter of ovarian carcinomas and might identify a subset of patients with different prognosis.

Different effects of H. pylori water extracts on cytokines, pepsinogen C and gastrin mucosal release in patients with or without duodenal ulcer

In the present study we ascertained whether cagA positive and negative H. pylori strains release water soluble products that can influence the production of gastric mucosal cytokines and endocrine (gastrin) or exocrine (pepsinogen C) secretion in 23 H. pylori positive and 19 H. pylori negative patients. Antral biopsies were obtained to classify inflammation, activity, atrophy, intestinal metaplasia and H. pylori density grade. The cagA gene was identified by means of the polymerase chain reaction (PCR) in H. pylori positive colonies after culture of mucosal samples. Three antral biopsies from each patient were incubated with (1.) Water extracts from cagA positive, (2.) Water extracts from cagA negative strains or (3.) H2O (control) at 37 degrees C in a CO2 incubator for 24 hrs. Gastrin, pepsinogen C, IL-1 beta, IL-8, GMCSF, and TNF alpha were measured in the supernatants and mucosal homogenates. H. pylori infection was significantly associated with an increased antral inflammation and activity (chi 2 = 21.7, p < 0.001 and chi 2 = 42.0, p < 0.001), and increased mucosal levels of IL-1 beta, IL-8 and TNF alpha. Water extracts from cagA positive strains enhanced the release of PGC in mucosal biopsy supernatants (p < 0.05) when patients were considered overall and the release of TNF alpha (p < 0.05) when only patients with duodenal ulcer were considered. Water extracts from cagA negative strains stimulated gastrin secretion (p < 0.05). None of the remaining cytokines were influenced by H. pylori water extracts. In conclusion, pepsinogen C and TNF alpha can be induced by cagA positive water extracts and may contribute to damage the gastric and duodenal mucosa. Our findings indicate that in patients with H. pylori infection the increase of the mucosal levels of IL-1 beta and IL-8 does not depend on H. pylori water soluble products, but probably depends on the entire bacterium.

Amphibian pepsinogens: purification and characterization of xenopus pepsinogens, and molecular cloning of Xenopus and bullfrog pepsinogens

Two pepsinogens (Pg C and Pg A) were isolated from the stomach of adult Xenopus laevis by Q-Sepharose, Sephadex G-75, and Mono-Q column chromatographies. Autolytic conversion and activation of the purified Pgs into the pepsins were examined by acid treatment. We determined the amino acid sequences from the NH2-termini of Pg C, pepsin C, Pg A, and pepsin A. Based on the sequences, the cDNAs for Pg C and Pg A were cloned from adult stomach RNA, and the complete amino acid sequences of the Pg C and Pg A were predicted. In addition, a Pg A cDNA was cloned from the stomach of adult bullfrog Rana catesbeiana, and the primary structure of the Pg A was predicted. Molecular phylogenetic analysis showed that such anuran Pg C and Pg A belong to the Pg C group and the Pg A group in vertebrates, respectively. The molecular properties of Pg C and Pg A, such as size, sequences of the activation peptide and active site, profile of autolytic activation, and pH dependency of proteolytic activity of the activated forms, pepsin C and pepsin A, resemble those of Pgs found in other vertebrates. However, the hemoglobin-hydrolyzing activity of Xenopus pepsin C is completely inhibited in the presence of equimolar pepstatin, an inhibitor of aspartic proteinases. Thus, the Xenopus pepsin C differs significantly from other vertebrate pepsins C in its high susceptibility to pepstatin, and closely resembles A-type pepsins.

Expression and prognostic significance of pepsinogen C in gastric carcinoma

BACKGROUND

In this study we evaluated the expression and clinical significance of pepsinogen C, an aspartic proteinase involved in the digestion of proteins in the stomach, in patients with gastric cancer.

METHODS

Pepsinogen C expression was examined by immunohistochemical methods in a series of 95 gastric carcinomas. The prognostic value of pepsinogen C was retrospectively evaluated by multivariate analysis taking into account conventional prognostic parameters. Follow-up period of patients was 21.4 months.

RESULTS

A total of 25 (26.3%) gastric carcinomas stained positively for pepsinogen C. The percentage of pepsinogen C-positive tumors was higher in well-differentiated (50%) than in moderately differentiated (19.5%) and poorly differentiated (21.9%) tumors (P < .05). Similarly, significant differences in pepsinogen C immunostaining were found between node-negative and node-positive tumors (47.1% vs. 14.7%; P < .001). In addition, statistical analysis revealed that pepsinogen C expression was associated with clinical outcome in gastric cancer patients. Low pepsinogen C levels predicted short overall survival periods in the overall group of patients with gastric cancer (P < .001), and in 71 patients with resectable carcinomas (P < .005). Multivariate analysis according to Cox's model indicated that pepsinogen C immunostaining was an independent predictor of outcome for both overall and resectable gastric cancer patients (P < .05, for both).

CONCLUSIONS

The expression of pepsinogen C in gastric cancer may represent a useful biological marker able to identify subgroups of patients with different clinical outcomes.

Factors that affect results of the 13C urea breath test in Japanese patients

BACKGROUND

The 13C urea breath test (UBT) is considered to be the most accurate way of diagnosing Helicobacter pylori infection. Our objective was to investigate the accuracy of the UBT in Japanese patients and the association of UBT values with histological findings.

MATERIALS AND METHODS

A total of 169 consecutive patients were studied by endoscopy with histology, by serology with IgG antibody and test serum pepsinogen (PG), and by UBT. The association between UBT values and histological findings and the PG I / II ratio were analyzed in H. pylori-positive patients.

RESULTS

Of 169 Japanese patients, 135 were H. pylori-positive on both histology and serology analysis, 27 were H. pylori-negative on both histology and serology analysis, and 7 patients showed differing results. Using a cutoff value of 2.5 per thousand, test sensitivity was 100%, while specificity was 96%. Among the 135 H. pylori-positive patients, a significant relation was observed between UBT value and H. pylori colonization density of the corpus and antrum, neutrophil activity of the antrum, atrophy, and intestinal metaplasia of the corpus in the H. pylori-positive patients. Also, UBT values correlated with the PG I /II ratio. In multivariate analysis, the PG I /II ratio was the most important factor related to UBT values (odds ration [OR], 4. 99; 95% confidence interval, 1.60-15.55).

CONCLUSIONS

The UBT is an accurate method for detecting H. pylori infection in the Japanese population, which shows a high prevalence of atrophic gastritis. Values are affected by H. pylori infection and by the severity of atrophic gastritis.

Structural aspects of activation pathways of aspartic protease zymogens and viral 3C protease precursors

The three-dimensional structures of the inactive protein precursors (zymogens) of the serine, cysteine, aspartic, and metalloprotease classes of proteolytic enzymes are known. Comparisons of these structures with those of the mature, active proteases reveal that, in general, the preformed, active conformations of the residues involved in catalysis are rendered sterically inaccessible to substrates by the residues of the zymogens' N-terminal extensions or prosegments. The prosegments interact in nonsubstrate-like fashions with the residues of the active sites in most of the cases. The gastric aspartic proteases have a well-characterized zymogen conversion pathway. Structures of human progastricsin, the inactive intermediate 2, and active human pepsin are known and have been used to define the conversion pathway. The structure of the zymogen precursor of plasmepsin II, the malarial aspartic protease, shows a new twist on the mode of inactivation used by the gastric zymogens. The prosegment of proplasmepsin disrupts the active conformation of the two catalytic aspartic acid residues by inducing a major reorientation of the two domains of the mature protease. The picornaviral 2A and 3C proteases have a chymotrypsin-like tertiary structure but with a cysteine nucleophile. These enzymes cleave themselves from the viral polyprotein in cis (intramolecular cleavage) and carry out trans cleavages of other scissile peptides important for the virus life cycle. Although the structure of the precursor viral polyprotein is unknown, it probably resembles the organization of the proenzymes of the bacterial serine proteases, subtilisin, and alpha-lytic protease. Cleavage of the prosegment is known to occur in cis for these precursor molecules.

Immunoenzymatically determined pepsinogen C concentration in breast tumor cytosols: an independent favorable prognostic factor in node-positive patients

The aim of this study was to determine the concentration and to evaluate the prognostic value of pepsinogen C (PepC) in breast cancer patients. PepC is an aspartic proteinase that is involved in the digestion of proteins in the stomach and is also synthesized by a subset of human breast tumors. PepC concentrations were measured with a highly sensitive immunofluorometric assay, which uses two monoclonal antibodies that are specific for PepC and has a detection limit of 0.1 ng/ml. Breast tumor cytosols from 151 patients (median follow-up, 67 months), stratified according to nodal status, were evaluated. An optimal cutoff value, equal to 1.75 ng/mg of extracted protein, was first defined by statistical analysis. PepC status was then compared with other established prognostic factors, in terms of disease-free survival (DFS) and overall survival (OS). High PepC concentrations were found in small (P = 0.003) and well-differentiated tumors (P = 0.042) as well as in stage I (P = 0.003) and node-negative patients (P = 0.040). Statistically significant associations of PepC concentration with patient age and estrogen receptor and progesterone receptor status were not observed. In univariate Cox regression analysis of the entire cohort of patients, negative PepC proved to be a significant predictor of reduced DFS (P = 0.0086) and OS (P = 0.025). Multivariate analysis in subgroups of patients defined by nodal status indicated that PepC status was a strong predictor of DFS (P = 0.0039) and the strongest factor for predicting OS (P = 0.0046) in node-positive but not in node-negative patients. Our results suggest that PepC may be used as an independent favorable prognostic factor in node-positive breast cancer patients because there were no significant associations between PepC and the other prognostic factors evaluated in this group of patients.

Expression of pepsinogen C in gynecomastias and male breast carcinomas

Pepsinogen C is a proteolytic enzyme involved in the digestion of proteins in the stomach; it is also synthesized by a significant percentage of female breast carcinomas. In addition, it has been demonstrated that pepsinogen C is one of the few proteins induced by androgens in breast carcinoma cells. Here we evaluate the expression of pepsinogen C by immunoperoxidase staining in normal breast tissue from 3 male patients, 15 gynecomastia tissues, 2 male in situ breast carcinomas, and 68 male invasive breast carcinomas. Pepsinogen C immunostaining values were quantified in male breast tumors using the HSCORE system, which considers both the intensity and the percentage of cells staining at each intensity. The results indicated positive immunohistochemical staining for pepsinogen C in all gynecomastia tissues, the two in situ ductal carcinomas, and 52 of 68 invasive breast carcinomas (76.4%). The three normal breast tissues analyzed showed negative staining for pepsinogen C, whereas invasive tumors showed clear differences among them with regard to the intensity and percentage of staining cells. In addition, pepsinogen C scores were significantly higher in well-differentiated (grade I, 188.7) and moderately differentiated (grade II, 145.8) tumors than in poorly differentiated (grade III, 98.5) tumors (p = 0. 032). Similarly, significant differences in pepsinogen C content were found between estrogen receptor (ER)-positive tumors and ER-negative tumors (158.5 vs. 44.3, respectively; p = 0.009). Patients with pepsinogen C-positive tumors reached longer relapse-free and overall survival periods than did those with tumors with negative staining, but no statistical differences were observed between survival curves calculated for these two groups of patients. This results demonstrate expression of pepsinogen C by gynecomastias and by a high percentage of male breast carcinomas and may indicate an important role of pepsinogen C in the pathophysiology of male breast diseases.

Basal and stimulated gastrin and pepsinogen levels after eradication of Helicobacter pylori: a 1-year follow-up study

AIM

A decrease in gastrin and pepsinogen (PG) levels 1 month after Helicobacter pylori eradication has been described repeatedly, but the long-term progression of such a decrease has been scarcely studied. We therefore studied the effect of H. pylori eradication on basal and stimulated gastrin and PG levels for 1 year. Initially, the usefulness of measuring these parameters for the noninvasive diagnosis of H. pylori eradication was validated. Furthermore, an assessment was made of the association between H. pylori reinfection and a re-increase in gastrin and PG values. Finally, an evaluation was made of the variables influencing gastrin and PG concentration, with particular attention to H. pylori infection and histological lesions of gastric mucosa.

METHODS

Two-hundred and twenty-two patients with duodenal ulcer were studied prospectively. Exclusion criteria were the administration of antibiotics, H2 antagonists, omeprazole or bismuth prior to endoscopy. In all patients serum basal levels of gastrin, PGI, and PGII were measured before and 1 month after completing eradication therapy. In the successfully eradicated patients, gastrin, PGI, and PGII were also measured at 6 and 12 months. In 80 patients stimulated measurements of gastrin (after ingestion of two beef cubes) and PGI (after injection of pentagastrin) were also performed. H. pylori-negative patients after therapy underwent a urea breath test at 6 and 12 months, and patients who had stimulated gastrin and PG concentration measured had also an endoscopy performed at 6 months.

RESULTS

H. pylori was eradicated in 73% of patients. A histological improvement was observed 1 month after completing H. pylori eradication therapy, both at gastric antrum and body (P < 0.001), while a further improvement at antrum was demonstrated at 6 months (P < 0.01). With regard to the different cut-off points for decreased basal and stimulated measurements for diagnosing H. pylori eradication, the best results were obtained, respectively, with PGII (sensitivity of 90% and specificity of 76%) and PGI 30 min after stimulation (sensitivity and specificity of 82%), with an area under the ROC curve of 0.87 in both cases. In the multiple regressions analysis H. pylori status correlated with gastrin, PGI and PGII after therapy (P < 0.001), while histological lesions correlated only with gastrin levels (P < 0.05). A decrease in basal and stimulated serum parameters was demonstrated immediately after eradication (Wilcoxon test, P < 0.001), and an additional decrease (at 6 months) was observed just in PGI (Friedman test, P < 0.01). However, gastrin and PGII values remained unchanged after the first month post-eradication. Seven patients were reinfected with H. pylori during follow-up. Quantitation of basal and stimulated gastrin and PGI levels was not reliable as a reinfection marker. Regarding basal PGII, the parallelism was strong at 6 months (re-increase in all four reinfected patients), although only in one out of three with reinfection at 1 year did PGII rise at that stage.

CONCLUSIONS

(1) Measurement of gastrin and PG levels (especially basal PGII values) is a useful non-invasive method to confirm H. pylori eradication after therapy. (2) H. pylori eradication is associated with a significant decrease in basal and stimulated gastrin levels and in basal PGII levels that is detected immediately (1 month) after finishing treatment, and remains unchanged for 1 year. However, the decrease in basal and stimulated PGI levels occurs progressively for 6 months, although such levels remain also unchanged afterwards. (3) Measurement of gastrin and PGI concentrations has a limited usefulness in the diagnosis of H. pylori reinfections after successful eradication, although PGII determination could be more useful in this situation.

Mechanism of activation of the gastric aspartic proteinases: pepsinogen, progastricsin and prochymosin

The gastric aspartic proteinases (pepsin A, pepsin B, gastricsin and chymosin) are synthesized in the gastric mucosa as inactive precursors, known as zymogens. The gastric zymogens each contain a prosegment (i.e. additional residues at the N-terminus of the active enzyme) that serves to stabilize the inactive form and prevent entry of the substrate to the active site. Upon ingestion of food, each of the zymogens is released into the gastric lumen and undergoes conversion into active enzyme in the acidic gastric juice. This activation reaction is initiated by the disruption of electrostatic interactions between the prosegment and the active enzyme moiety at acidic pH values. The conversion of the zymogen into its active form is a complex process, involving a series of conformational changes and bond cleavage steps that lead to the unveiling of the active site and ultimately the removal and dissociation of the prosegment from the active centre of the enzyme. During this activation reaction, both the prosegment and the active enzyme undergo changes in conformation, and the proteolytic cleavage of the prosegment can occur in one or more steps by either an intra- or inter-molecular reaction. This variability in the mechanism of proteolysis appears to be attributable in part to the structure of the prosegment. Because of the differences in the activation mechanisms among the four types of gastric zymogens and between species of the same zymogen type, no single model of activation can be proposed. The mechanism of activation of the gastric aspartic proteinases and the contribution of the prosegment to this mechanism are discussed, along with future directions for research.

Detection of blotted antigen using a fusion protein between protein A and pepsinogen C

Human pepsinogen (PG) A and C were fused with protein A and expressed in Escherichia coli. Although the fusion proteins (PA-PGA and PA-PGC) were not expressed at high levels and were almost totally recovered from the insoluble fraction, the renaturation and purification procedures were easy and simple. PA-PGA and PA-PGC possessed proteolytic activity equivalent to the gastric mucosal PGA and PGC, respectively. However, the activity of PA-PGC was about 3-fold higher than that of PA-PGA. Therefore, PA-PGC was applied to the subsequent immunoblotting studies. The proteolytic activity of PA-PGC was used for digesting the blocking reagent around the target antigen (in situ digestion method) or casein-clotting in the agarose plate containing skimmed milk (caseogram print method). Although the sensitivity of these methods was lower than that of the conventional color detection, the caseogram print method was superior in that the reaction was linear over a wide range. On the other hand, the in situ digestion method possessed a unique property on Western blotting, and it was very easy to identify the relative position of the target, which could be recognized as a clear band. For PA-PGC detection, no special chemicals are required, and so the procedure is simple, rapid, and inexpensive.