Expression of p21(WAF1/CIP1) and p53 proteins in gastric carcinoma: its relationships with cell proliferation activity and prognosis

Gastric adenocarcinoma of the fundic gland type: A review of the literature

Background and Aim

Gastric adenocarcinoma of the fundic gland type (GA-FG) is a newly described tumor entity but lacking consensus. This review summarizes the key features and controversies regarding this uncommon neoplasm.

Methods

We reviewed studies on GA-FG published in English from 2007 to 2021.

Results

We found that 327 cases (340 lesions) have been reported. GA-FG lesions originate from deep layers of the gastric mucosa, with the following characteristics on conventional white-light endoscopy examination. These lesions, macroscopically identified as submucosal tumor-like 0-IIa, tend to have a whitish discoloration without inflammation, atrophy, or intestinal metaplasia in the background mucosa. Tumors located in the upper third of the stomach are usually solitary, with an average size <10 mm. Contrastingly, magnifying endoscopy with narrow-band imaging mostly shows the absence of any demarcation line, with a regular microvascular pattern and regular microsurface pattern. GA-FGs are covered with normal foveolar epithelium, forming a so-called endless glands pattern in the deeper region, which are mainly composed of chief cells or parietal cells. Most tumors exhibit submucosal invasion, but lymphovascular invasion and nodal metastasis are rare. Regarding the treatment of GA-FG, endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) are effective treatment methods.

Conclusions

GA-FG is a rare tumor that typically follows a benign course. This neoplasm has distinct endoscopic and pathological features and could be treated by ESD or EMR.

Isoforms of the p53 Family and Gastric Cancer: A Ménage à Trois for an Unfinished Affair

Simple Summary

The p53 family is a complex family of transcription factors with different cellular functions that are involved in several physiological processes. A massive amount of data has been accumulated on their critical role in the tumorigenesis and the aggressiveness of cancers of different origins. If common features are observed, there are numerous specificities that may reflect particularities of the tissues from which the cancers originated. In this regard, gastric cancer tumorigenesis is rather remarkable, as it is induced by bacterial and viral infections, various chemical carcinogens, and familial genetic alterations, which provide an example of the variety of molecular mechanisms responsible for cell transformation and how they impact the p53 family. This review summarizes the knowledge gathered from over 40 years of research on the role of the p53 family in gastric cancer, which still displays one of the most elevated mortality rates amongst all types of cancers.

Abstract

Gastric cancer is one of the most aggressive cancers, with a median survival of 12 months. This illustrates its complexity and the lack of therapeutic options, such as personalized therapy, because predictive markers do not exist. Thus, gastric cancer remains mostly treated with cytotoxic chemotherapies. In addition, less than 20% of patients respond to immunotherapy. TP53 mutations are particularly frequent in gastric cancer (±50% and up to 70% in metastatic) and are considered an early event in the tumorigenic process. Alterations in the expression of other members of the p53 family, i.e., p63 and p73, have also been described. In this context, the role of the members of the p53 family and their isoforms have been investigated over the years, resulting in conflicting data. For instance, whether mutations of TP53 or the dysregulation of its homologs may represent biomarkers for aggressivity or response to therapy still remains a matter of debate. This uncertainty illustrates the lack of information on the molecular pathways involving the p53 family in gastric cancer. In this review, we summarize and discuss the most relevant molecular and clinical data on the role of the p53 family in gastric cancer and enumerate potential therapeutic innovative strategies.

Ki-67/MKI67 as a Predictive Biomarker for Clinical Outcome in Gastric Cancer Patients: an Updated Meta-analysis and Systematic Review involving 53 Studies and 7078 Patients

Gastric cancer (GC) threatens human health worldwide and we performed this meta-analysis to evaluate the clinical value of Ki-67/MKI67 in patients with GC. The combined hazard ratio (HR), odds ratio (OR) and 95% confidence interval (95% CI) were calculated to assess the relationships of Ki-67/MKI67 expression with prognoses and clinicopathological characteristics. Genes co-expressed with MKI67 were collected for Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and protein-protein interaction (PPI) network analyses. In total, 53 studies with 7078 patients were included in this study. The pooled HRs indicated that an elevated expression of Ki-67/MKI67 predicted an unfavorable overall survival (HR: 1.54, 95% CI: 1.33-1.78, P<0.0001) and disease-free survival (HR: 2.28, 95% CI: 1.43-3.64, P<0.0001) in GC patients. Additionally, in patients with advanced GC, a high Ki-67/MKI67 expression was also significantly connected with OS (HR: 1.37, 95% CI: 1.18-1.60, P<0.0001). The combined ORs showed that Ki-67/MKI67 expression was related to TNM stage (stage III/IV versus stage I/II: OR=1.93, 95% CI=1.34-2.78, P<0.0001), tumor differentiation (poor versus well/moderate: OR=1.94, 95% CI=1.32-2.85, P=0.001), lymph node metastasis (yes versus no: OR=1.67, 95% CI=1.23-2.25, P=0.001), distant metastasis (yes versus no: OR=1.67, 95% CI=1.24-2.26, P=0.001) and tumor invasion depth (T3/T4 versus T_is/T1/T2: OR=1.98, 95% CI=1.60-2.44, P<0.0001). The results of GO, KEGG pathway and PPI network analyses indicated that Ki-67/MKI67 may be involved in the development of GC via influencing P53 signaling pathway. Ki-67/MKI67 could be a potential indicator to predict the prognosis of patients with GC and identify high-risk cases. Detecting Ki-67/MKI67 expression in clinic may be helpful in optimizing individual treatment and further improving the survival expectancy of patients with GC.

Clinicopathologic significance and prognostic value of Ki-67 expression in patients with gastric cancer: a meta-analysis

BACKGROUND

The prognostic value and clinicopathologic significance of Ki-67 expression in gastric cancer patients was controversial. This meta-analysis was performed to clarify the prognostic value and clinicopathologic significance of Ki-67 expression in gastric cancer patients.

MATERIALS AND METHODS

Several electronic databases were searched for eligible studies. The pooled odds ratio (OR), hazard ratios (HR) and 95% confidence interval(CI) were calculated to explore the prognostic value and clinicopathologic significance of Ki-67 expression for disease free survival and overall survival.

RESULTS

Totally 5600 gastric cancer patients from 29 studies were included in this study. High Ki-67 expression was significantly related with Lauren's classification (OR = 1.70; P = 0.001; 95%CI: 1.40-2.06) and tumor size(OR = 1.54; P = 0.006; 95%CI: 1.14-2.09). However, high Ki-67 expression was not significantly associated with lymph node metastasis (OR = 1.37; P = 0.138; 95% CI: 0.90-2.08) , tumor stage (OR = 1.31; P = 0.296; 95% CI: 0.79-2.16) and tumor differentiation (OR = 1.03; P = 0.839; 95% CI: 0.78-1.35). The pooled HRs were 1.87(P = 0.001; 95% CI 1.30-2.69) for disease free survival and 1.23(P = 0.005; 95% CI 1.06-1.42) for overall survival.

CONCLUSIONS

High Ki-67 expression may serve as a predictive biomarker for poor prognosis in gastric cancer patients. Stratification by Ki-67 expression may be a consideration for selection of therapeutic regimen and integrated managements.

Meta-analysis of prognostic role of Ki-67 labeling index in gastric carcinoma

BACKGROUND

This meta-analysis aimed to elucidate the prognostic role of the Ki-67 labeling index (LI) in gastric cancer (GC).

METHODS

The current study included 3,615 GC patients in 20 eligible studies, and evaluated the prognostic role of Ki-67 LI in GC. Subgroup analysis was conducted based on depth of invasion and cutoff value for high Ki-67 LI.

RESULTS

A high Ki-67 LI correlated significantly with worse survival (hazard ratio [HR] = 1.214, 95% confidence interval [CI], 1.004-1.468). However, there was no significant correlation between high Ki-67 LI and worse survival in advanced GC (HR = 1.252, 95% CI, 0.801-1.956). The subgroup with cutoff value ≤25% showed a significant correlation with worse survival, but this was not seen in the subgroup with cutoff >25% (HR = 1.433, 95% CI, 1.094-1.876 vs. HR = 1.005, 95% CI, 0.801-1.262). In addition, in the 10% <Ki-67 LI ≤ 20% range, there was a significant correlation between high Ki-67 LI and worse overall survival (HR = 1.931, 95% CI, 1.013-3.310).

CONCLUSIONS

A high Ki-67 LI correlated significantly with a worse prognosis in GC patients. Further cumulative studies for the optimal cutoff value for high Ki-67 LI are needed before application in clinical practice.

Omeprazole promotes carcinogenesis of fore-stomach in mice with co-stimulation of nitrosamine

Objectives

To investigate if oral omeprazole application induces cancers of fore and glandular stomach in mice.

Methods

A total of 66 eligible male mice were randomly divided into 6 groups, which were treated with control reagent, low (6 mg/kg) and high dose omeprazole (30 mg/kg), N-methyl-N’-nitro-N-nitrosoguanidine (MNNG, 100 mg/L water), and MNNG plus low and high dose omeprazole, respectively. After 24 weeks, concentrations of acid phosphatase (ACP) and N-acetyl-β-D-glucosaminidase(NAG) in serum and spleen was examined, and p21 and mTOR levels in stomach were detected.

Results

The mouse spleen weight index was smaller in the omeprazole group than the control group, and in the MNNG plus omeprazole groups than the MNNG group. In the fore-stomach, more carcinomas were observed in the MNNG plus omeprazole groups than in the MNNG group. In the glandular stomach, there existed more atypical hyperplasia cases in the MNNG plus omeprazole groups than the MNNG-treated group, and one carcinoma was induced in the MNNG plus high dose omeprazole group. Omeprazole alone caused minor gastric pathological changes. Omeprazole treatment lowered both serum and spleen ACP and NAG levels in both the non-MNNG-treated and MNNG-treated subgroups. In fore-stomach, there existed decreased p21 and mTOR levels in the omeprazole-treated groups than in the control group, and in the MNNG plus omeprazole groups than the MNNG-treated group.

Conclusion

Omeprazole promotes carcinogenesis of the mouse fore-stomach but not the glandular stomach following treatment with MNNG. Lysosomal hydrolase activity was inhibited and some cancer-associated proteins was dysregulated, which requires further explorations.

Prognostic significance of p53 in gastric cancer: a meta- analysis

BACKGROUND

Gastric cancer is one of the frequently seen cancers in the world and it is the second most common reason for death due to cancer. The prognostic role of expression of p53 detected by immunohistochemistry in gastric cancer remains controversial. This meta-analysis aimed to explore any association between overexpression and survival outcomes.

MATERIALS AND METHODS

We systematically searched for studies investigating the relationships between expression of p53 detected by immunohistochemistry and prognosis of gastric cancer patients. Study quality was assessed using the Newcastle-Ottawa Scale. After careful review, survival data were extracted from eligible studies. A meta-analysis was performed to generate combined hazard ratios for overall survival and disease-free survival.

RESULTS

A total of 4.330 patients from 21 studies were included in the analysis. Our results showed tissue p53 overexpression in patients with gastric cancer to be associated with poor prognosis in terms of overall survival (HR, 1.610; 95% CI, 1.394 -5.235; p: <0.001). Pooled hazard ratio for disease free survival showed that p53 positivity or negativity were not statitistically significant (HR, 1.219; 95%CI, 0.782-1.899; p:0.382).

CONCLUSIONS

The present meta-analysis indicated overexpression of p53 detected by immunohistochemistry to be associated with a poor prognosis in patients with gastric cancer.

Clinicopathological and prognostic significance of p53, Ki-67, and Bcl-2 expression in Tunisian gastric adenocarcinomas

Gastric carcinoma (GC) is a highly aggressive malignancy with poor prognosis. It is widely accepted that malignancy results from abnormal cell growth due to dysregulation of the balance between cell proliferation and apoptosis. Our study aimed to investigate the clinicopathological and prognostic significance of p53, Ki-67, and Bcl-2 in Tunisian GC patients by immunohistochemistry. It was observed that the older patients showed p53 overexpression compared with the younger patients (p<0.05). There was higher p53 expression in the intestinal-type compared with the diffuse-type (p<0.05), and in well/moderate differentiated than in poor differentiated tumors. The expression of Ki-67 was positively associated with tumor size and venous invasion (p<0.05). Bcl2 expression occurred in male patients and correlated with depth of invasion (p=0.02). A Kaplan-Meier analysis indicated an inverse correlation between p53 and Ki-67 expression and the overall survival. Multivariate analysis revealed that the tumor site, Ki-67 and p53 expression were independent prognostic factors for gastric carcinomas (p<0.05). Finally, combined expression of p53, Ki-67 and Bcl-2 showed that the group of patients with tumors p53+/Ki-67+/Bcl2- had aggressive behavior and poor prognosis (p log rank=0.000). In summary, our data indicated that the expression of p53, Ki-67, and Bcl-2 may provide useful information for identifying patients with aggressive behavior and poor prognosis of GC.

Decreased expression of RASSF6 is a novel independent prognostic marker of a worse outcome in gastric cancer patients after curative surgery

BACKGROUND

Our previous study observed that the expression of RASSF6, a member of the Ras-association domain family, was down-regulated in gastric cancer cells. The present study further investigated the clinical significance of RASSF6 in gastric cancer.

METHODS

Using real-time PCR, Western blot analysis, tissue microarray (TMA), and immunohistochemical staining, we evaluated RASSF6 mRNA and protein levels in tumor tissues and in the paired adjacent normal mucosa from patients with gastric cancers at different stages.

RESULTS

RASSF6 mRNA and protein levels were decreased in gastric cancer tissues compared with the adjacent normal mucosa. Immunohistochemical detection of RASSF6 in a TMA that contained 264 paired specimens showed that a decreased cytoplasmic RASSF6 expression was significantly associated with the extent of cancer invasion, lymph node metastasis, distant metastasis, tumor histological grade, advanced clinical stage, and Ki-67 proliferative index. Moreover, RASSF6 expression in metastatic lymph nodes was lower than in the paired primary tumors. Patients with RASSF6-negative tumors had extremely higher disease recurrence rates and poorer survival than patients with RASSF6-positive tumors even after radical surgery. Stratification analysis revealed RASSF6 as an independent predictor for tumor recurrence in patients with gastric cancers irrespective of tumor stage.

CONCLUSIONS

RASSF6 might contribute to the progression of gastric carcinogenesis and may function as a novel independent prognostic marker for the prediction of the recurrence of cancer in patients after curative operations.

Low Ki-67 proliferation index is an indicator of poor prognosis in gastric cancer

BACKGROUND AND OBJECTIVES

We designed this study to assess the biologic significance of Ki-67 proliferation index (PI) in gastric cancer.

METHODS

Gastric cancer tissue from 245 patients were immunostained for Ki-67. Ki-67 PI was defined as the percentage of tumor cells positive for Ki-67. In addition, we have previously evaluated the expressions of nine epithelial mesenchymal transition (EMT)-related proteins. The relationship between Ki-67 PI and clinicopathologic parameters, patient survival, and EMT data were sought.

RESULTS

Low Ki-67 PI was correlated with poorly differentiated histology (P = 0.034), an advanced T stage (P < 0.001), and lymph node metastasis (P = 0.011). Also, the low PI group was found to have a significantly worse prognosis than the high PI group (P = 0.003, log-rank test). Multivariate analysis revealed that Ki-67 PI remained as an independent prognostic factor (hazard ratio (95% CI) = 0.670 (0.450-0.999)). Furthermore, greater expressional changes of EMT-related proteins were found to be significantly associated with low Ki-67 PI (P = 0.025).

CONCLUSIONS

These findings suggest that Ki-67 PI is an effective tool for predicting survival in gastric cancer. In addition, we found that an invasive property presented as EMT-related protein expressional changes was inversely correlated with a proliferative activity in gastric cancer.

CagA(+) H. pylori induces Akt1 phosphorylation and inhibits transcription of p21(WAF1/CIP1) and p27(KIP1) via PI3K/Akt1 pathway

OBJECTIVE

Cytotoxin-associated protein (CagA) of H. pylori has been confirmed to be closely associated with gastric inflammation and tumorigenesis, but the mechanism behind it is little understood. In this study, we try to determine roles of CagA(+) strain in activating PI3K/Akt1 signaling pathway, and affecting expression of p21(WAF1/CIP1) and p27(KIP1), and also in releasing IL-8 in host cells.

METHODS

Akt1 phosphorylation and IL-8 levels of CagA(+) and CagA⁻ strain infected AGS cells were detected by ELISAs. Two quantitative RT-PCRs were established to measure p21(WAF1/CIP1) and p27(KIP1) mRNA levels in the CagA(+) and CagA⁻ strain infected cells. LY294002, an inhibitor of PI3K/Akt pathway, was used to define effect of the pathway in IL-8 release.

RESULTS

CagA(+) strain could induce an obvious elevation of Akt1 phosphorylation in the infected AGS cells while CagA? strain failed to do so. The CagA(+) H. pylori strain infected AGS cells showed significant drops both in p21(WAF1/CIP1) and p27(KIP1) mRNA levels, whereas the CagA⁻ H. pylori strain caused a remarkable increase in p21(WAF1/CIP1) mRNA without affecting p27(KIP1) gene transcription in the AGS cells. Both the CagA(+) and CagA⁻ H. pylori strains enabled AGS cells to produce close elevated levels of IL-8, and the LY294002 block resulted in unexpected elevations of IL-8 levels.

CONCLUSIONS

CagA can activate PI3K/Akt1 pathway that plays an inhibitory role in IL-8 release in H. pylori infected AGS cells. Activation of PI3K/Akt1 pathway and subsequent negative regulation of p21(WAF1/CIP1) and p27(KIP1) expression might be involved in CagA-associated carcinogenesis.

COX-2 is associated with proliferation and apoptosis markers and serves as an independent prognostic factor in gastric cancer

Cyclooxygenase-2 (COX-2) is an important factor in gastric carcinogenesis, and COX-2 expression in gastric cancer patients correlates with prognosis. We have now studied the impact of COX-2 in comparison to six other tissue tumor markers, DNA index, and S-phase fraction (SPF) in a large series of gastric cancer specimens. From 342 consecutive patients, 337 archival tissue specimens were available for immunohistochemistry of COX-2, HuR, cyclin A, MMP-2, p53, p21, and Ki-67 and 313 for analysis of DNA index and S-phase fraction by flow cytometry. Associations between factors were assessed by chi-square test and survival analysis by the Kaplan-Meier method and Cox model. A significant association emerged between of COX-2 and p53 (p < 0.0001), Ki-67 (p = 0.013), DNA ploidy (p < 0.0001), and SPF (p < 0.0001). In an extended multivariate analysis, COX-2 and p53 expression were independent prognostic factors for poor survival, in addition to high stage and non-curative surgery. In gastric cancer, COX-2 expression associated with markers for apoptosis and proliferation, and furthermore, it was confirmed that COX-2 and p53 are strong prognostic indicators.

Anticancer effect of celecoxib via COX-2 dependent and independent mechanisms in human gastric cancers cells

Cyclooxygenase-2 (COX-2) inhibitors cause growth inhibition of human gastric carcinoma cells, but it remains unclear whether this is both COX-2 dependent and independent. The related mechanisms remain to be determined. Both low COX-2 expressing gastric carcinoma and high COX-2 expressing gastric carcinoma cells were used to study the effect and mechanisms of celecoxib on gastric carcinoma cell growth. Celecoxib resulted in comparable growth inhibition in AGS cells with stable transfections of small interfering RNA (siRNA) against COX-2 (SAC) and negative control vector (NC) cells. Simultaneously, celecoxib resulted in significant reduction of Bcl-2 and significant increase of p21(WAF1) and p27(KIP1) in SAC and NC cells. The present study shows that celecoxib causes growth inhibition of gastric carcinoma cells by decreasing Bcl-2 of cyclooxygenase-2-dependent pathway, and by increasing p21(WAF1) and p27(KIP1) of cyclooxygenase-2-independent pathway. These data extend our knowledge on the effect and mechanisms of celecoxib-induced inhibition of gastric carcinoma cell growth.

Cytogenetic and molecular aspects of gastric cancer: clinical implications

Gastric cancer is of major importance world-wide being the second most common cause of cancer-related death in the world. According to Lauren's histological classification gastric cancer is divided in two groups, the better differentiated intestinal carcinomas and the poorly differentiated diffuse-type cancers. The genetic changes underlying the initiation and progression of gastric cancer are not well defined. Gastric carcinogenesis is a multistep process involving a number of genetic and epigenetic factors. Although it has been proposed that different genetic pathways exist for differentiated and undifferentiated carcinomas, the two histological subtypes of gastric cancer share some common genetic alterations. Currently, tumor histology and pathologic stage are the major prognostic variables used in the clinical practice for gastric cancer patients. However, it is known that tumors with similar morphology may differ in biological aggressiveness, prognosis and response to treatment. Molecular genetic analysis of gastric cancer revealed a number of associations of certain genetic changes with pathological features, tumor biological behavior and prognosis of gastric cancer patients, suggesting that these genetic abnormalities might play an important role in gastric tumorigenesis. Increasing evidence suggests that the molecular genetic changes could be helpful in the clinical setting, contributing to prognosis and management of patients. Regarding epigenetic events in gastric tumorigenesis, a number of methylating markers have been proposed for risk assessment, prognostic evaluation and as therapeutic targets. However, further research is required in order to systematically investigate the genetic changes in gastric cancer estimating also their usefulness in the clinical practice. A good understanding of the genetic changes underlying gastric carcinogenesis may provide new perspectives for prognosis and screening of high risk individuals. Some of the genetic alterations could definitely improve tumor classification and management of gastric cancer patients. Also, based on molecular data identified in gastric cancer novel therapeutics might help to improve the treatment of this disease.

Expression of p21WAF in salivary gland mucoepidermoid carcinoma and its relation to histologic grade

The biologic behavior and factors influencing the development of salivary gland mucoepidermoid carcinoma are not fully understood. Alteration of the cyclin-dependant kinase inhibitor p21(WAF) could cause uncontrolled proliferation leading to cancer. Thirty-five mucoepidermoid carcinomas were graded and immunohistochemically stained for p21(WAF). The percentage of positive tumor cells was determined using an eyepiece graticule and a computer-assisted image analyzer, which revealed 8.6% and 22.9% of the cases to be positive for p21(WAF), respectively. A statistically significant correlation was not observed between p21(WAF) and grading. Considering the absence of p21(WAF) expression in most mucoepidermoid carcinomas, it appears that the inhibitory effect of p21(WAF) on cell growth is removed in most cases. Given the lack of correlation with tumor grade, it is possible that the impact of p21(WAF) is in the earlier stages of tumorigenesis. A p53-independent pathway of p21(WAF) induction may exist for the small proportion of tumors that showed positivity.

Expression of cyclooxygenase-2, p53 and Ki-67 in gastric cancer

It has been reported that p53 mutation may contribute to upregulate cyclooxygenase (COX)-2 expression that is observed in malignant tissues. These molecules are involved in carcinogenesis by affecting tumor cell proliferation. The aim of this study was to examine the relationship between COX-2 or p53 expression and clinico-pathological characteristics including tumor cell proliferation in gastric cancer. COX-2 and p53 expressions were investigated with immunostaining, in tissue specimens obtained from 119 patients who underwent surgery for gastric cancer. The Ki-67 labeling index (LI) was counted by Ki-67 immunostaining. COX-2 and p53 expressions correlated significantly with depth of tumor invasion. However, there was no association between COX-2 or p53 expression and survival. p53 expression did not correlate with COX-2 expression. There was no significant difference in various clinicopathological variables between Ki-67 LI subgroups. The mean Ki-67 LI value of COX-2 positive tumors was significantly higher than that of negative tumors. The mean Ki-67 LI value of p53 positive tumors was not significantly higher than that of negative tumors. The mean Ki-67 LI value of both COX-2 and p53 positive tumors was significantly higher than that of both negative tumors. These results imply that COX-2 expression is associated with tumor cell proliferation of gastric cancer.

The prognostic significance of p53, p27 kip1, p21 waf1, HER-2/neu, and Ki67 proteins expression in gastric cancer: a clinicopathological and immunohistochemical study of 121 Arab patients

BACKGROUND

The variability of prognosis within a pathological stage of gastric cancer (GC) at presentation, underscores the need for specific biological markers to identify subgroups of patients with aggressive course for intensive treatment. To our knowledge, this is the first study from an Arab population reporting on the relationship of p53, p27 kip1, p21 waf1, HER-2/neu, and Ki67 expression, and clinicopathological features and their prognostic significance.

METHODS

Formalin-fixed paraffin-embedded tumors were studied by immunohistochemistry, using monoclonal antibodies to p53, p27 kip1, p21 waf1, HER-2/neu, and Ki67. The results were correlated with clinicopathological features and survival.

RESULTS

M:F = 80:41; median age = 60 years; stage III and IV = 71%; and median follow-up = 34.4 months. Positive expression rates of p53, p27 kip1, p21 waf1, Ki67, and HER-2/neu were 54%, 40%, 8.3%, 70%, and 12% respectively. p53 expression correlated with age <60 years (P = 0.03), tumor size >5 cm (P = 0.01), p27 kip1 and Ki67 expression (P = 0.0001), and HER-2/neu (P = 0.04). p21 waf1 correlated inversely with T-stage (P = 0.008) and Her-2/neu expression correlated with histological grade (P = 0.04) and T-stage (P = 0.008). Univariate analysis showed that p53 overexpression (P = 0.01), fungating and infiltrative macroscopic appearance (P = 0.02), size >5 cm (P = 0.0001), lymph node metastasis (P = 0.0001), p T3 and T4 disease (P = 0.01), and overall stage III and IV (P = 0.0001) disease were adverse prognostic factors. Patients with tumor profiles p53 (-)/p27 (+) had better survival than those with p53 (+)/p27 kip1 (-)(P = 0.02). On multivariate analysis by Cox regression model, the expression of p53 (P = 0.03) and lymph node involvement (P = 0.01) were significant adverse prognostic factors for overall survival.

CONCLUSIONS

The expression of p53 in Arab patients with GC correlates with aggressive tumor characteristics and is an independent prognostic factor. The combined analysis of p53 and p27 kip1 is of added prognostic value.

Cell proliferation, apoptosis and the related regulators p27, p53 expression in hepatocellular carcinoma

AIM: To investigate the expression of cell apoptosis, proliferation and the related regulators p27, p53 in hepatocellular carcinoma (HCC).

METHODS: The expression of p27, p53, proliferating cell nuclear antigen (PCNA) and apoptosis in 47 HCC specimens and 42 surrounding non-cancerous tissues were detected by the immunohistochemistry and terminal deoxy-nucleotidyl transferase-mediated nick end labeling (TUNEL) technique. Meanwhile, the clinical significance of them was analyzed combining with the clinicopathological factors and follow-up data.

RESULTS: (1) The average proliferating index and apoptotic index in HCC were significantly higher than that in adjacent liver tissues. The proliferating index was associated with extrahepatic metastasis. The apoptotic index was significantly lower in TNM stage I-II than in stage III-IV. The proliferating index of groups with p53-/p27+ was significantly lower than that in group with p53+/p27- (P = 0.030); (2) The level of p27 in the cytoplasmic fraction was higher in non-tumoral liver tissues and was associated with clinical stage; (3) Survival analysis showed advanced stage (P = 0.031) and with extrahepatic metastasis (P = 0.045) was significantly associated with shorter survival. In addition, the prognosis of patients with p53-/p27+ was longer than that of patients with p53+/p27- (P = 0.0356).

CONCLUSION: The p53 mutation and decreased p27 expression might be involved in the imbalance of proliferation and apoptosis in HCC. Cytoplasmic displacement might lead to the inactivation of p27 protein in HCC cells and acts early during carcinogenesis of HCC. The combined examination of p27, and p53 expression allows reliable estimation of prognosis for patients with primary hepatic carcinoma.

Expression of reg I alpha protein in human gastric cancers

BACKGROUND/AIMS

Although regenerating gene(Reg) I alpha protein has a trophic effect on gastric epithelial cells, it is unclear whether Reg I alpha protein and its receptor are involved in gastric carcinogenesis. Therefore, we investigated the Reg I alpha protein expression in human gastric cancers and assessed its relationship to clinicopathological factors.

METHODS

Sixty-one gastric cancer specimens were examined, using immunohistochemistry, for Reg I alpha protein, p53, and proliferating cell nuclear antigen. The expression of both Reg I alpha and Reg receptor mRNA was examined in seven human gastric cancer cell lines (MKN1, MKN28, MKN45, MKN74, KATOIII, GCIY, and AGS) by reverse transcription-polymerase chain reaction and Northern blot analysis.

RESULTS

Twenty-three (37.7%) of the 61 gastric cancer tissues samples were positive for Reg I alpha protein. The Reg I alpha expression was significantly related to the presence of lymphatic invasion but not to tumor size, tumor stage, Lauren's classification, presence of venous invasion, lymph node metastases, or p53 overexpression. Gastric cancers positive for Reg I alpha protein showed a significantly higher proliferating cell nuclear antigen labeling index than negative ones. The expression of both Reg I alpha and Reg receptor mRNA was detected in all seven gastric cancer cell lines.

CONCLUSION

Reg I alpha protein may play a role in the development of gastric cancers.

Molecular Pathological Analysis of Mucinous Adenocarcinomas of the Stomach

OBJECTIVE

Mucinous adenocarcinomas (MACs) of the stomach usually show an invasive expansive growth and a poor prognosis. We examined the possibility of molecular pathological subtyping of MACs of the stomach.

METHODS

Forty-one formalin-fixed and paraffin-embedded MAC specimens of the stomach were analyzed. Mucin subtypes (MUC2, CD10, HGM, M-GGMC-1) and expression levels of hMLH1, p53 and Ki-67 were analyzed by immunohistochemistry as well as genetic alterations in the p53 gene and microsatellite instability (MSI).

RESULTS

According to both MSI and p53 status, these tumors were subclassified into three groups: the mutator-type tumors, the suppressor/p53-type tumors and the unclassified tumors. The mutator-type tumors demonstrated lower p53 expression and had lower proliferative activity than the suppressor/p53-type tumors, whereas most of the suppressor/p53-type tumors expressed CD10. However, there was no significant difference between the mutator- and suppressor/p53-type tumors in clinicopathological parameters including the patients' outcome.

CONCLUSION

Our results indicate that MACs of the stomach are composed of at least three subtypes according to the molecular pathological background for their carcinogenesis. Further study of carcinomas with detailed morphological and biological phenotyping of each subtype may provide useful information for better clinical management.

Expressão da proteína P53 no adenocarcinoma gástrico: correlação clínica, anatomopatológica e significância prognostica

OBJETIVO: Avaliar a expressão da proteína p53 no adenocarcinoma gástrico e correlacioná-la com variáveis clínicas e anatomopatológicas, tais como: idade, sexo, infiltração da parede gástrica (T), tipo histológico (Laurén), grau de diferenciação histológica, comprometimento linfonodal, estadiamento (TNM) e sobrevida. MÉTODO: Foram analisados os registros médicos e reestudadas as lâminas de peças cirúrgicas de 45 doentes com adenocarcinomas gástricos submetidos à gastrectomia parcial e total no Serviço de Cirurgia Oncológica da Santa Casa de Misericórdia de Maceió-AL e no Hospital Universitário da Universidade Federal de Alagoas, no período de 1991 a 2002. A expressão da proteína p53 foi avaliada pelo método imunohistoquímico com o anticorpo monoclonal DO-7 e comparada com idade, sexo, infiltração na parede gástrica, tipo histológico, grau de diferenciação, comprometimento linfonodal, estadiamento e sobrevida. RESULTADOS: Dos 45 doentes, 27 eram do sexo masculino (60%). A média das idades foi 53,9 anos (26 - 75 anos), e mediana de 57 anos. Em 40 doentes (88,9%) o tumor foi classificado como bem diferenciado. Quanto à infiltração na parede gástrica, em 28 doentes (62,2%) foram classificados como profundos. Em 25 doentes (55,6%) não havia comprometimento linfonodal. O estudo histológico revelou que 29 doentes (64,4%) apresentavam tumores classificados como tipo intestinal de Laurén. O estadiamento TNM demonstrou que 33 (73,3%) doentes apresentavam tumores avançados. Quanto à expressão da p53, 18 doentes (40%) foram considerados positivos. O tempo médio de seguimento foi de 1020,4 dias (63 - 3920 dias) e mediana de 798 dias. Trinta e um (68,9%) doentes evoluíram para óbito. As variáveis: idade, estadiamento, comprometimento linfonodal e infiltração do tumor na parede gástrica, foram fatores prognósticos relacionados à sobrevida com significado estatístico (p<0,05). Não houve correlação estatística significativa da proteína p53 com as variáveis estudadas. A análise estatística multivariada identificou apenas o comprometimento linfonodal como fator prognóstico independente. CONCLUSÕES: Os autores concluíram que dezoito (40%) dos doentes expressaram a reação imunohistoquímica para p53. Não houve correlação estatística significativa da expressão da proteína p53 com os fatores prognósticos estudados. A expressão da proteína p53 não foi fator prognóstico independente.

Expression of p21(WAF1) and p53 and polymorphism of p21(WAF1) gene in gastric carcinoma

AIM

To investigate the relationship between expression of p21(WAF1) and p53 gene, and to evaluate the deletion and polymorphism of p21(WAF1) gene in gastric carcinoma (GC).

METHODS

Expression of p21 and p53 proteins, and deletion and polymorphism of p21 gene in GC were examined by streptavidin-peroxidase conjugated method (SP) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) respectively.

RESULTS

The expression of p21 and p53 was found in 100% (20/20) and 0% (0/20) of normal gastric mucosae(NGM), 92.5% (37/40) and 15.0% (6/40) of dysplasia (DP) and 39.8% (43/108) and 56.5% (61/108) of GC, respectively. The positive rate of p21 in GC was lower than that in NGM and DP (P<0.05), while the positive rate of p53 in GC was higher than that in NGM and DP (P<0.05). p21 and p53 were significantly expressed in 63.3% (19/30) and 36.7% (11/30), 35.0% (14/40) and 77.5% (31/40), 26.7% (4/15) and 80.0% (12/15), 30.8% (4/13) and 30.8% (4/13), and 20.0% (2/10) and 30.0% (3/10) of well-differentiated, poorly-differentiated, undifferentiated carcinomas, mucoid carcinomas and signet ring cell carcinomas. The expression of p21 in well-differentiated carcinomas was significantly higher than that in poorly-differentiated, un-differentiated, mucoid carcinomas and signet ring cell carcinomas (P<0.05). Contrarily, The expression of p53 was increased from well-differentiated to poorly-differentiated and un-differentiated carcinomas (P<0.05). The expression of p21 and p53 in paired primary and metastatic GC (35.3% and 70.6%) was different from non-metastatic GC (62.5% and 42.5%) markedly (P<0.05). The expression of p21 in invasive superficial muscle (60.0%) was higher than that in invasive deep muscle or total layer (35.2%) (P<0.05) and was higher in TNM stages I (60.0%) and II (56.2%) than in stages III (27.9%) and IV (22.2%) (P<0.05), whereas the expression of p53 did not correlate to invasion depth or TNM staging (P>0.05). The exoression patterns of p53+/p21-, and of p53-/p21+ were found in 5.0% and 82.5% of DP. There was a significant correlation between expression of p21 and p53 (P<0.05). But there was no significant correlation between expression of both in GC (P>0.05). There was no deletion in exon 2 of p21 gene in 30 cases of GC and 45 cases of non-GC, but polymorphism of p21 gene at exon 2 was found in 26.7% (8/30) of GC and 8.9% (4/45) of non-GC, a significant difference was found between GC and non-GC (P<0.05). There was no significant relation between p21 expression of polymorphism (37.5%, 3/8) and non-polymorphism (45.5%, 10/22) in GC (P>0.05).

CONCLUSION

The loss of p21 protein and abnormal expression of p53 are related to carcinogenesis, differentiation and metastasis of GC. The expression of p21 is related to invasion and clinical staging in GC intimately. The expression of p21 protein depends on p53 protein largely in NGM and DP, but not in GC. No deletion of p21 gene in exon 2 can be found in GC. The polymorphism of p21 gene might be involved in gastric carcinogenesis.There is no significant association between polymorphism of p21 gene and expression of p21 protein.

A gene encoding an apurinic/apyrimidinic endonuclease-like protein is up-regulated in human gastric cancer

AIM: To identify the gene that may predispose to human gastric cancer and to analyze its expression in gastric cancer and non-tumorous gastric mucosa.

METHODS: Cancer, para-tumor, and non-tumor gastric tissues were studied for gene expression profile using fluorescent differential display reverse transcription polymerase chain reaction (DDRT-PCR). The differentially expressed bands of interest were analyzed by cloning, Northern blotting, and sequencing. The sequencing results were compared with the GenBank database for homology and conserved domain analysis. In situ hybridization with DIG-labeled cRNA probes was used to detect the expression of gene in paraffin embedded gastric adenocarcinoma and non-cancerous tissues.

RESULTS: A gene expressed higher in tumor and para-tumor tissues than in their non-tumor counterparts of all 7 tested gastric adenocarcinoma patients was identified by means of DDRT-PCR analysis. It was named GCRG213 (gastric cancer related gene 213). Northern blot confirmed the differential expression. GCRG213 (GenBank No. AY053451) consisted of 1094 base pairs with an open reading frame (ORF) which encoded 142 amino acids. The deduced amino acid sequence contained a putative conserved domain, apurinic/apyrimidinic endonuclease (APE). In situ hybridization analysis showed that GCRG213 was expressed higher in gastric cancer tissues than in their corresponding non-tumor ones. Precancerous leisions of gastric adenocarcinoma showed a high GCRG213 expression, too. No difference of the expression patterns was found between the early and advanced gastric cancer.

CONCLUSION: A gene named GCRG213 was identified in human gastric adenocarcinoma. It encoded an APE-like protein which was probably a new member of the APE family. GCRG213 was over-expressed not only in gastric cancer, but also in its precancerous leisions. The role of GCRG213 expression in carcinogenesis needs further study.

p21WAF1 expression in invasive breast cancer and its association with p53, AP-2, cell proliferation, and prognosis

AIMS

To evaluate the expression and prognostic relevance of p21(WAF1) in breast cancer and to investigate its association with p53, activator protein 2 (AP-2), and cell proliferation (as assessed by Ki-67 expression).

METHODS

p21(WAF1) expression was analysed immunohistochemically in a large prospective, consecutive series of 420 patients with breast cancer diagnosed and treated between 1990 and 1995 at Kuopio University Hospital, Kuopio, Finland. Inter-relations between p21(WAF1) expression and p53, AP-2, and Ki-67 were evaluated. The expression of p21(WAF1) was also compared with clinicopathological parameters and the patients' survival.

RESULTS

In general, nuclear p21(WAF1) expression was low in carcinomas (median, 2.5%; range, 0-70%). Expression was lowest in lobular carcinomas (chi(2) = 7.4; p = 0.025). p21(WAF1) positive tumours were more often p53 positive (chi(2) = 4.2; p = 0.041) but expression of p21(WAF1) did not correlate with AP-2 expression or Ki-67 in the whole patient group. In addition, the combined expression of p21 and p53 was not associated with AP-2 expression. High nuclear p21(WAF1) positivity (n = 160; 38%) was associated with poor differentiation (chi(2) = 8.1; p = 0.017). In the univariate analyses, p21(WAF1) expression had no prognostic value for predicting breast cancer related survival (BCRS) or recurrence free survival (RFS) in the whole patient group or in the subgroups investigated. However, in postmenopausal patients with lymph node metastases, and oestrogen receptor (ER) and/or progesterone receptor (PR) positive tumours, high p21(WAF1) expression predicted response to adjuvant hormonal treatment with antioestrogens. In the univariate analysis, the significant factors for predicting BCRS were Ki-67 expression, stage, lymph node status, histological grade, ER and PR status, and those for RFS were Ki-67 expression, stage, and lymph node status. In the multivariate analysis, the independent predictors of shorter BCRS were high cell proliferation activity measured by Ki-67 expression (p < 0.001), advanced stage (p < 0.001), and poor differentiation (p = 0.048). Shorter RFS was independently predicted by high cell proliferative activity (p < 0.001) and advanced stage (p < 0.001).

CONCLUSIONS

The regulation of p21(WAF1) seems to occur independently of p53 or AP-2 and analysing p21(WAF1) expression provided no prognostic information for patients with breast cancer.

TP53 and gastric carcinoma: a review

In this article, we survey the major p53 (TP53) alterations identified in gastric carcinomas and their precursors. These include p53 expression, mutations, and loss of heterozygosity (LOH). Not only are the various abnormalities summarized, but in addition there is a survey of the literature with respect to the impact of these changes on patient prognosis and treatment response. The majority of published studies involve the immunohistochemical detection of the protein. These use different antibodies, different detection techniques, and different methods of interpretation. Therefore not surprisingly, the results of many of the studies are contradictory with one another. Overall, however, it appears that p53 alterations occur early in the development of gastric carcinoma, being present even in the nonneoplastic mucosa and they increase in frequency as one progresses along the pathway of gastric carcinoma development. p53 immunoreactivity is seen in 17%-90.7% of invasive gastric carcinomas. p53 alterations occur much more commonly in proximal lesions than in distal ones, suggesting that the molecular events leading to the development of gastric carcinoma may be very different in proximal vs. distal tumors. p53 mutations occur in 0%-77% of gastric carcinomas. The mutations are distributed widely across the gene from exons 4-11 with hot spots of mutation at codons 175, 248, 273, 282, 245, and 213. G:C>A:T transitions at CpG sites are the commonest type of mutation. At least 60% of carcinomas with mutations also exhibit p53 LOH.

A novel gene, GCRG224, is differentially expressed in human gastric mucosa

AIM: To clone genes that may predispose us to human gastric cancer and to analyze it’s expression in gastric tissues.

METHODS: Specimens of paired tumor, paratumor and normal gastric mucosa tissues collected from fifteen patients who suffered from stomach antrum adenocarcinoma were used for analysis. Seven out of the fifteen cases were first studied by fluorescent differential display reverse transcription polymerase chain reaction (DDTR-PCR) analysis. The differentially expressed bands of interest were cloned, analyzed by Northern blot, sequencing and RT-PCR. Through BLAST, the sequencing results were compared with GenBank database for homology analysis. In situ hybridization with DIG-labeled cRNA probes was used to analyze the expression of interesting cDNA bands in paraffin embedded paired normal gastric mucosa and cancer tissues isolated from 30 gastric adenocarcinoma patients.

RESULTS: DDRT-PCR showed that one of the interesting cDNA bands, which was named W2, expressed much higher in all seven tested tumor and paratumor samples than in their normal counterparts, it was sub-cloned into a pGEM-T Easy vector. Two subclones were subsequently obtained. One of the subclone, GCRG224, was studied further. The sequencing result showed that GCRG224 consisted of 1159 base pairs and had one open reading frame (ORF). It located at human chromosome 11q14. No homologue was found in GenBank database with GCRG224-ORF. This nucleotide sequence data were submitted to GenBank with accession No. AF438406. RT-PCR showed that GCRG224 expressed higher in 11/15 gastric cancer tissues than in non-tumor tissues. However, the result of Northern blot analysis showed a higher GCRG224 expression in the non-tumor tissue than in the tumor one. Human multiple tissue Northern blot analysis revealed that GCRG224 also expressed in human normal colon tissue, and peripheral blood leukocyte. In situ hybridization analysis showed that only 5/30 adenocarcinoma, 3/18 dysplasia and 6/18 intestinal metaplasia showed higher GCRG224 expression level than the normal gastric glands. However, GCRG224 was over-expressed predominantly in 26/30 cases of normal mucosal epithelium.

CONCLUSION: A novel gene named GCRG224 was identified from human gastric mucosal tissue. It overexpressed in almost all gastric mucosal epithelium but only a small portion of cancer and precancerous leisions. The role of GCRG224 expression in gastric epithelium needs further study.

Autocrine human growth hormone inhibits placental transforming growth factor-beta gene transcription to prevent apoptosis and allow cell cycle progression of human mammary carcinoma cells

Multiple cellular effects of human growth hormone (hGH) are mediated by an indirect mechanism requiring transcriptional activation of genes encoding protein effector molecules such as insulin-like growth factor-1. Such protein effector molecules then act directly to mediate the cellular functions of hGH. We report here that autocrine hGH production by mammary carcinoma cells specifically results in the transcriptional repression of the p53-regulated placental transforming growth factor-beta (PTGF-beta) gene. Transcriptional repression of the PTGF-beta gene does not require the p53-binding sites in the PTGF-beta promoter, and autocrine hGH also desensitized the response of the PTGF-beta promoter to p53 overexpression. Transcriptional repression of the PTGF-beta gene is accompanied by consequent decreases in its protein product, Smad-mediated transcription, and its cellular effects that include cell cycle arrest and apoptosis. PTGF-beta specifically inhibited the autocrine hGH-stimulated expression of cyclin D1 required for autocrine hGH-stimulated mammary carcinoma cell cycle progression. Thus, one mechanism by which autocrine hGH promotes an increase in mammary carcinoma cell number is by transcriptional repression of protein effector molecules that promote cell cycle arrest and apoptosis. Such transcriptional repression of negative regulatory factors, such as PTGF-beta, may also be requisite for direct stimulation of mammary carcinoma cell mitogenesis by hGH.