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

Redefining aberrant P53 expression of gastric cancer and its distinct clinical significance among molecular-histologic subtypes

BACKGROUND

Numerous studies have demonstrated a correlation between p53 overexpression and diminished survival in gastric cancer patients. However, conflicting findings exist, and we hypothesize that these discrepancies arise from the cancer's complexity and heterogeneity, coupled with a lack of consensus on aberrant p53 expression.

METHODS

We enrolled a cohort of 187 patients with surgically resected gastric cancer. Patient categorization was based on Epstein-Barr virus (EBV), microsatellite instability (MSI), and Lauren classification (intestinal, diffuse and mixed). Utilizing an incremental algorithm, we evaluated p53 immunohistochemical (IHC) patterns in all 187 cases, while next-generation sequencing was successfully performed on 152 cases to identify TP53 mutations (mutTP53).

RESULTS

MutTP53 was identified in 32 % of the 152 cases, comprising 36 missense, 5 nonsense, and 7 frameshift alterations. Missense mutations predominantly correlated with p53 overexpression, while nonsense and frameshifting alterations related to null expression. Trial calculations indicated that null expression and a p53 IHC cutoff at >40 % offered the best prediction of mutTP53 (kappa coefficient, 0.427), with the highest agreement (0.524) observed in diffuse type and the lowest (0.269) in intestinal type. Null expression and a p53 IHC cutoff at >10 %, but not mutTP53 per se, provided the optimal prediction of survival outcome (p = 0.043), particularly in diffuse type (p = 0.044). Multivariate analysis showed that aberrant p53 IHC expression was not an independent prognostic factor.

CONCLUSIONS

P53 IHC patterns are predictive biomarkers for mutTP53 and gastric cancer outcomes, where a prerequisite involves a nuanced approach considering cutoff values and molecular-histologic subtyping.

Unraveling the influence of LncRNA in gastric cancer pathogenesis: a comprehensive review focus on signaling pathways interplay

Gastric cancers (GCs) are among the most common and fatal malignancies in the world. Despite our increasing understanding of the molecular mechanisms underlying GC, further biomarkers are still needed for more in-depth examination, focused prognosis, and treatment. GC is one among the long non-coding RNAs, or lncRNAs, that have emerged as key regulators of the pathophysiology of cancer. This comprehensive review focuses on the diverse functions of long noncoding RNAs (lncRNAs) in the development of GC and their interactions with important intracellular signaling pathways. LncRNAs affect GC-related carcinogenic signaling cascades including pathways for EGFR, PI3K/AKT/mTOR, p53, Wnt/β-catenin, JAK/STAT, Hedgehog, NF-κB, and hypoxia-inducible factor. Dysregulated long non-coding RNA (lncRNA) expression has been associated with multiple characteristics of cancer, such as extended growth, apoptosis resistance, enhanced invasion and metastasis, angiogenesis, and therapy resistance. For instance, lncRNAs such as HOTAIR, MALAT1, and H19 promote the development of GC via altering these pathways. Beyond their main roles, GC lncRNAs exhibit potential as diagnostic and prognostic biomarkers. The overview discusses CRISPR/Cas9 genome-modifying methods, antisense oligonucleotides, small molecules, and RNA interference as potential therapeutic approaches to regulate the expression of long noncoding RNAs (lncRNAs). An in-depth discussion of the intricate functions that lncRNAs play in the development of the majority of stomach malignancies is provided in this review. It provides the groundwork for future translational research in lncRNA-based whole processes toward GC by highlighting their carcinogenic effects, regulatory roles in significant signaling cascades, and practical scientific uses as biomarkers and therapeutic targets.

Polymorphism of apoptosis marker genes in the blood of indigenous people with gastric cancer in the Republic of Tyva

Introduction. Russia is among the leaders in incidence and mortality from gastric cancer (GC). The incidence of gastric cancer in the Republic of Tyva is especially abnormally high. Currently, there is interest in studying genetic factors in various types of cancer. But for GC, such research is not enough.

Aim. To study the polymorphism of the apoptosis marker genes CASP9 (rs1052576), TP53 (rs1042522), FAS/APO-1 (rs2234767) in the blood of indigenous people with GC in the Republic of Tyva.

Materials and methods. 107 Tuvinians were examined (47 people with GC and 60 persons in the control group). The diagnosis of GC was established on the basis of a comprehensive laboratory, instrumental and morphological examination by oncologists at the Republican Oncology Dispensary. Genotyping of polymorphisms rs1052576 CASP9, rs2234767 FAS/APO-1 and rs1042522 TP53 was carried out in all 47 patients with GC and in 60 people in the control group using the polymerase chain reaction method from DNA samples isolated from venous blood.

Results. In patients with GC, compared with healthy individuals, the mutant allele G (44.7% versus 27.5%; p = 0.01) and the homozygous genotype GG (23.4% versus 6.7%; p = 0.03) of polymorphism rs1042522 TP53, as well as mutant allele A (57.4% versus 32.5%; p < 0.001) and homozygous genotype AA (31.9% versus 15.0%; p = 0.05) of polymorphism rs2234767 FAS/ APO-1 were more often registered among indigenous inhabitants of the Republic of Tyva. The frequency of various genotypes and alleles of the polymorphism rs1052576 CASP9 did not differ significantly between patients with GC and healthy individuals.

Conclusion. Based on these results, it can be assumed that the A allele of rs2234767 FAS/APO-1 and the disruption of the anti-oncogenic function of the p53 protein produced by the G allele of rs1042522 TP53 are associated with GC and can be used as markers to determine increased risk in the population of indigenous residents of the Republic of Tyva.

Implementing an integrated molecular classification for gastric cancer from endoscopic biopsies using on-slide tests

The availability of more effective biological therapy can improve outcomes of gastric cancer (GC), but most patients do not have access to personalized treatment. GC molecular classification helps identify patients suitable for specific therapies and provides useful prognostic information. To date, only a small number of patients have access to molecular classification. We proposed a working molecular classification that can be delivered using on-slide tests available in most histopathology laboratories. We used eight on-slide tests [in situ hybridization (ISH) for Epstein-Barr virus-encoded small ribonucleic acid (EBER) and immunohistochemistry (IHC) for MutL homolog 1 (MLH1), PMS1 homolog 2 (PMS2), MutS homolog 2 (MSH2), MutS homolog 6 (MSH6), E-cadherin, β-catenin and p53] to classify GC into one of six categories: GC associated with Epstein-Barr virus (GC-EBV), GC mismatch repair deficient (GC-dMMR), GC with epithelial-mesenchymal transition (GC-EMT), GC with chromosomal instability (GC-CIN), GC genomically stable (GC-GS) and GC not otherwise specified (GC-NOS)∕indeterminate. The classification has provision also for current and future on-slide companion diagnostic (CDx) tests necessary to select specific biological therapies and, as proof of principle, in this study we used three CDx tests currently required for the management of GC [human epidermal growth factor receptor 2 (Her2), programmed cell death-ligand 1 (PD-L1) 22C3 and Claudin18.2 (CLDN18.2)]. This paper describes the necessary tissue pathways and laboratory workflow and assesses the feasibility of using this classification prospectively on small endoscopic biopsies of gastric and gastroesophageal junction adenocarcinoma. This work demonstrates that such molecular classification can be implemented in the context of a histopathology diagnostic routine with little impact on turnaround times and laboratory capacity. The widespread adoption of a molecular classification for GC will help refine prognosis and guide the choice of more appropriate biological therapy for these patients.

Molecular Classifications in Gastric Cancer: A Call for Interdisciplinary Collaboration

Gastric cancer (GC) is a heterogeneous disease, often diagnosed at advanced stages, with a 5-year survival rate of approximately 20%. Despite notable technological advancements in cancer research over the past decades, their impact on GC management and outcomes has been limited. Numerous molecular alterations have been identified in GC, leading to various molecular classifications, such as those developed by The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG). Other authors have proposed alternative perspectives, including immune, proteomic, or epigenetic-based classifications. However, molecular stratification has not yet transitioned into clinical practice for GC, and little attention has been paid to alternative molecular classifications. In this review, we explore diverse molecular classifications in GC from a practical point of view, emphasizing their relationships with clinicopathological factors, prognosis, and therapeutic approaches. We have focused on classifications beyond those of TCGA and the ACRG, which have been less extensively reviewed previously. Additionally, we discuss the challenges that must be overcome to ensure their impact on patient treatment and prognosis. This review aims to serve as a practical framework to understand the molecular landscape of GC, facilitate the development of consensus molecular categories, and guide the design of innovative molecular studies in the field.

A novel immunohistochemical score predicts the postoperative prognosis of gastric cancer patients

BACKGROUND AND AIM

Immunohistochemistry indicators are increasingly being used to predict the survival prognosis of cancer patients after surgery. This study aimed to combine some markers to establish an immunohistochemical score (MSI-P53-Ki-67[MPK]) and stratify postoperative patients with gastric cancer according to the score.

METHODS

We used 245 patients who underwent surgery at one center as the training cohort and 111 patients from another center as the validation cohort. All patients were treated between January 2012 and June 2018. The training cohort was screened for prognostic factors, and MPK scores were established using univariate and multifactorial COX risk proportional models. Patients were prognostically stratified according to the MPK score after gastrectomy for gastric cancer. Overall survival (OS) and recurrence-free survival (RFS) rates were compared among low-, intermediate-, and high-risk groups using the Kaplan-Meier method, and survival curves were plotted. Finally, the MPK score was validated using the validation cohort.

RESULTS

In the training group, there were statistically significant differences in OS and RFS in the low, medium, and high-risk groups (P < 0.001). Thirty patients were in the high-risk group (12.2%). The median survival times of the three groups were 64.0, 44.0, and 23.0, respectively, and median times to recurrence were 54.0, 35.0, and 16.0 months, respectively. In the validation group, the prognosis in the three risk groups remained significantly different (P < 0.001).

CONCLUSIONS

The novel MPK score could effectively predict the postoperative OS and RFS of gastric cancer patients, risk-stratify postoperative patients, and identify postoperative high-risk patients for refined management.

In silico analysis to identify novel ceRNA regulatory axes associated with gallbladder cancer

Competitive endogenous RNA (ceRNA) networks are reported to play a crucial role in regulating cancer-associated genes. Identification of novel ceRNA networks in gallbladder cancer (GBC) may improve the understanding of its pathogenesis and might yield useful leads on potential therapeutic targets for GBC. For this, a literature survey was done to identify differentially expressed lncRNAs (DELs), miRNAs (DEMs), mRNAs (DEGs) and proteins (DEPs) in GBC. Ingenuity pathway analysis (IPA) using DEMs, DEGs and DEPs in GBC identified 242 experimentally observed miRNA-mRNA interactions with 183 miRNA targets, of these 9 (CDX2, MTDH, TAGLN, TOP2A, TSPAN8, EZH2, TAGLN2, LMNB1, and PTMA) were reported at both mRNA and protein levels. Pathway analysis of 183 targets revealed p53 signaling among the top pathway. Protein-protein interaction (PPI) analysis of 183 targets using the STRING database and cytoHubba plug-in of Cytoscape software revealed 5 hub molecules, of which 3 of them (TP53, CCND1 and CTNNB1) were associated with the p53 signaling pathway. Further, using Diana tools and Cytoscape software, novel lncRNA-miRNA-mRNA networks regulating the expression of TP53, CCND1, CTNNB1, CDX2, MTDH, TOP2A, TSPAN8, EZH2, TAGLN2, LMNB1, and PTMA were constructed. These regulatory networks may be experimentally validated in GBC and explored for therapeutic applications.

Evaluation of Tumor DNA Sequencing Results in Patients with Gastric and Gastroesophageal Junction Adenocarcinoma Stratified by TP53 Mutation Status

Background

Gastric cancer (GC) and gastroesophageal junction adenocarcinomas (GEJ) are molecularly diverse. TP53 is the most frequently altered gene with approximately 50% of patients harboring mutations. This qualitative study describes the distinct genomic alterations in GCs and GEJs stratified by TP53 mutation status.

Patients and Methods

Tumor DNA sequencing results of 324 genes from 3741 patients with GC and GEJ were obtained from Foundation Medicine. Association between gene mutation frequency and TP53 mutation status was examined using Fisher’s exact test. Functional gene groupings representing molecular pathways suggested to be differentially mutated in TP53 wild-type (TP53WT) and TP53 mutant (TP53MUT) tumors were identified. The association of the frequency of tumors containing a gene mutation in the molecular pathways of interest and TP53 mutation status was assessed using Fisher’s exact test with a P-value of &lt;.01 deemed statistically significant for all analyses.

Results

TP53 mutations were noted in 61.6% of 2946 GCs and 81.4% of 795 GEJs (P &lt; .001). Forty-nine genes had statistically different mutation frequencies in TP53WT vs. TP53MUT patients. TP53WT tumors more likely had mutations related to DNA mismatch repair, homologous recombination repair, DNA and histone methylation, Wnt/B-catenin, PI3K/Akt/mTOR, and chromatin remodeling complexes. TP53MUT tumors more likely had mutations related to fibroblast growth factor, epidermal growth factor receptor, other receptor tyrosine kinases, and cyclin and cyclin-dependent kinases.

Conclusion

The mutational profiles of GCs and GEJs varied according to TP53 mutation status. These mutational differences can be used when designing future studies assessing the predictive ability of TP53 mutation status when targeting differentially affected molecular pathways.

A Network Pharmacology Perspective Investigation of the Pharmacological Mechanisms of the Herbal Drug FDY003 in Gastric Cancer

Gastric cancer (GC) is one of the most common and deadly malignant tumors worldwide. While the application of herbal drugs for GC treatment is increasing, the multicompound–multitarget pharmacological mechanisms involved are yet to be elucidated. By adopting a network pharmacology strategy, we investigated the properties of the anticancer herbal drug FDY003 against GC. We found that FDY003 reduced the viability of human GC cells and enhanced their chemosensitivity. We also identified 8 active phytochemical compounds in FDY003 that target 70 GC-associated genes and proteins. Gene ontology (GO) enrichment analysis suggested that the targets of FDY003 are involved in various cellular processes, such as cellular proliferation, survival, and death. We further identified various major FDY003 target GC-associated pathways, including PIK3-Akt, MAPK, Ras, HIF-1, ErbB, and p53 pathways. Taken together, the overall analysis presents insight at the systems level into the pharmacological activity of FDY003 against GC.

HER-2 positivity is a high risk of recurrence of stage I gastric cancer

BACKGROUND/AIMS

The treatment of gastric cancer remains unsatisfactory. We aimed to investigate the prognostic value of immunohistochemical staining in gastric cancer.

METHODS

We analyzed 505 (279 early staged, 226 advanced-staged) gastric cancer tissues from patients who underwent radical gastric resection between January 2014 and December 2016. Available surgical specimens immunohistochemically stained for p53, epidermal growth factor receptor (EGFR), human EGFR 2 (HER-2), E-cadherin, and Ki-67 were reviewed. We evaluated the association between positivity to various biomarkers and disease recurrence, disease-free survival, lymph node metastasis, and microscopic lymphovascular invasion.

RESULTS

The median follow-up duration was 32.5 months (range, 7 to 70). Advanced gastric cancer cases showed high Ki-67 expression; other cases showed unremarkable expression. Concerning disease recurrence, lymphatic invasion, and disease-free interval, all biomarkers had no prognostic effects. HER-2-positive stage I gastric cancer tended to occur in old patients and in the upper one-third of the stomach (p = 0.01). HER-2 positivity was significantly correlated with disease recurrence (p = 0.01), lymphatic invasion (p = 0.03), and vascular invasion (p = 0.03) in stage I cases.

CONCLUSION

Only HER-2 was associated with the recurrence of stage I gastric cancer. HER-2-positive stage I gastric cancer requires additional therapy despite curative resection.

Different effects of p53 protein overexpression on the survival of gastric cancer patients according to Lauren histologic classification: a retrospective study

BACKGROUND

Inactivation of TP53, a tumor suppressor gene, is associated with the development of several malignancies, including gastric cancer (GC). The present study aimed to evaluate the correlation between the overexpression of p53 and survival in different Lauren-type GCs.

METHODS

From May 2003 to December 2019, 3608 GC patients treated endoscopically or surgically at the Seoul National University Bundang Hospital were enrolled for the study. Immunohistochemical staining for p53 was performed on all endoscopic and surgical gastric specimens. Clinicopathologic characteristics with Lauren classification, survival rate, and cancer recurrence were analyzed according to p53 overexpression.

RESULTS

Among 3608 GC patients, p53 overexpression was seen in 1334 patients (37%). p53 overexpression was associated with lower depth of invasion (P = 0.026) and Early gastric cancer (P = 0.044) in intestinal-type GC, and with advanced TNM stage (P < 0.001) and Advanced gastric cancer (P < 0.001) in diffuse-type GC. The overall survival (OS) and GC-specific survival (GCSS) were significantly lower in p53 overexpression positive patients. This significance was more pronounced and enhanced in the diffuse-type GC and was absent in the intestinal-type GC. In multivariate analyses, p53 overexpression was associated with poor OS in both subtypes of GC and cancer recurrence in diffuse-type GC. (OS in intestinal-type: adjusted hazard ratio [aHR] = 1.423, P = 0.022; OS in diffuse-type: aHR = 1.401 P = 0.035; cancer recurrence in diffuse-type: aHR = 1.502, P = 0.039).

CONCLUSION

p53 overexpression was associated with poor prognosis in GC, especially in diffuse-type. In addition, p53 overexpression was associated with early stage disease in intestinal-type GC and with advanced stage disease in diffuse-type GC.

MicroRNA‑10b modulates cisplatin tolerance by targeting p53 directly in lung cancer cells

MicroRNA (miRNA or miR)‑10b is an oncogenic miRNA associated with metastasis that is present in various types of tumor, including lung cancer. However, whether miR‑10b is involved in different malignant characteristics, such as drug resistance or stemness, remains unclear. Therefore, the present study investigated whether miR‑10b is an upstream regulator of p53. Ectopic expression of miR‑10b‑agomir decreased the expression of p53 and its downstream effectors, such as Bax and p53 upregulated modulator of apoptosis. Two non‑canonical sites, including 1,580‑1,587 and 2,029‑2,035, located in p53 3'‑untranslated region (UTR) were affected by the presence of miR‑10b. In functional assays, upregulation of the p53 signaling pathway following cisplatin treatment was associated with decreased levels of miR‑10b and upregulation of the luciferase activity of wild‑type, but not 1,584, 2,032‑dual‑mutant, p53 3'‑UTR. The ectopic expression of miR‑10b‑agomir attenuated the stability of p53 3'‑UTR and the expression of p53 and its downstream effectors induced by cisplatin. By contrast, the knockdown of miR‑10b induced the stability of p53 3'‑UTR and increased levels of p53 and the sensitivity of A549 cells to cisplatin treatment. Similar results were also observed for Beas 2B cells. In the clinical investigation, p53 exhibited two distinct associations (cocurrent and countercurrent) with miR‑10b in patients with lung cancer. Patients with lung cancer with low p53 and high miR‑10b levels exhibited the poorest prognosis, while those with high p53 and low miR‑10b exhibited the most favorable prognosis. These findings indicate a novel pathway in which cisplatin induces the levels of p53 by increasing mRNA stability via miR‑10b, indicating a novel oncogenic role of miR‑10b in promoting the malignant characteristics of non‑small cell lung carcinoma.

The Prognostic Significance of c-Met and p53 Immunohistochemical Expression in Gastric and Colorectal Carcinomas

BACKGROUND: Colorectal and gastric carcinomas are the most common and deadly gastrointestinal (GIT) malignancies. AIM: This study aimed to evaluate the expression of c-Met and p53 in gastric and colorectal carcinomas (CRCs) as well as colorectal adenomas using immunohistochemistry. MATERIALS AND METHODS: c-Met and p53 immunohistochemical expression was conducted on 66 cases of gastric adenocarcinomas and total of 60 colonic cases (36 CRCs and 24 colorectal adenomas). RESULTS: In this study, c-Met was positively expressed in 54.5% of gastric carcinomas and 50% of CRCs. In addition, p53 was positively expressed in 56.1% of gastric carcinomas and 72.2% of CRCs. Moreover, higher expression of both c-Met (p = 0.001) and p53 expression (p < 0.001) was reported in CRCs compared to colorectal adenomas. In the same context, c-Met and p53 expressions were positively correlated with intestinal type gastric adenocarcinoma (p < 0.001 and p = 0.03, respectively). Moreover, c-Met was correlated with non-mucinous adenocarcinomas (p = 0.008) and lower grades (p < 0.001) of gastric carcinomas. As regard survival analysis in gastric carcinomas, median overall survival (OS) was better in p53 positive patients (p = 0.05), patients with negative lymph node metastasis (p = 0.03), and patients with better response to neoadjuvant chemotherapy (p = 0.04). In contrast, c-Met did not exhibit significant correlation with OS (p > 0.05). Both c-Met and p53 did not reveal significant correlation with tumor stage and site in both CRCs and gastric carcinomas (p > 0.05). CONCLUSION: We concluded that c-Met and p53 are expressed in the most common GIT malignancies addressing them as potential biomarkers. In addition, c- Met and p53 may have a potential role in colorectal cancer development as they showed higher positivity in CRCs compared to adenomas.

Prediction of TP53 mutations by p53 immunohistochemistry and their prognostic significance in gastric cancer

Background

Recently, molecular classifications of gastric cancer (GC) have been proposed that include TP53 mutations and their functional activity. We aimed to demonstrate the correlation between p53 immunohistochemistry (IHC) and TP53 mutations as well as their clinicopathological significance in GC.

Methods

Deep targeted sequencing was performed using surgical or biopsy specimens from 120 patients with GC. IHC for p53 was performed and interpreted as strong, weak, or negative expression. In 18 cases (15.0%) with discrepant TP53 mutation and p53 IHC results, p53 IHC was repeated.

Results

Strong expression of p53 was associated with TP53 missense mutations, negative expression with other types of mutations, and weak expression with wild-type TP53 (p<.001). The sensitivity for each category was 90.9%, 79.0%, and 80.9%, and the specificity was 95.4%, 88.1%, and 92.3%, respectively. The TNM stage at initial diagnosis exhibited a significant correlation with both TP53 mutation type (p=.004) and p53 expression status (p=.029). The Kaplan-Meier survival analysis for 109 stage II and III GC cases showed that patients with TP53 missense mutations had worse overall survival than those in the wild-type and other mutation groups (p=.028). Strong expression of p53 was also associated with worse overall survival in comparison to negative and weak expression (p=.035).

Conclusions

Results of IHC of the p53 protein may be used as a simple surrogate marker of TP53 mutations. However, negative expression of p53 and other types of mutations of TP53 should be carefully interpreted because of its lower sensitivity and different prognostic implications.

Impact of Tumor Localization and Molecular Subtypes on the Prognostic and Predictive Significance of p53 Expression in Gastric Cancer

We investigated the prognostic and predictive impact of p53 expression for gastric cancer (GC) patients treated without or with preoperative chemotherapy (CTx) and its relationship with specific molecular GC subtypes. Specimens from 694 GC patients (562 surgical resection specimens without or after CTx, 132 biopsies before CTx) were analyzed by p53 immunohistochemistry. High (H) and low (L) microsatellite instability (MSI) and Epstein–Barr virus positivity were determined previously. Our results show that aberrant p53 expression was a negative prognostic factor in uni- and multivariable analysis in the resection specimens cohort (each p < 0.01). Subgroup analysis showed the strongest prognostic effect for patients with distally located tumors or no CTx treatment. In the biopsy cohort before CTx, p53 did not predict response or survival. p53 expression was significantly different among the molecular subtypes in surgical resection and bioptic specimens with strong association of altered p53 with MSI-L. Patients with MSI-H and aberrant p53 showed the worst survival in the biopsy cohort. In conclusion, the prognostic impact of p53 in GC differs according to tumor localization and CTx. Altered p53 is characteristic for MSI-L, and the p53 status in biopsies before CTx delineates MSI-H subtypes with inverse prognostic impact.

A Review of Research Progress in Multidrug-Resistance Mechanisms in Gastric Cancer

Gastric cancer is one of the most common malignant tumors, and it is also one of the leading causes of cancer death worldwide. Because of its insidious symptoms and lack of early dictation screening, many cases of gastric cancer are at late stages which make it more complicated to cure. For these advanced-stage gastric cancers, combination therapy of surgery, chemotherapy, radiotherapy and target therapy would bring more benefit to the patients. However, the drug-resistance to the chemotherapy restricts its effect and might lead to treatment failure. In this review article, we discuss the mechanisms which have been found in recent years of drug resistance in gastric cancer. And we also want to find new approaches to counteract chemotherapy resistance and bring more benefits to the patients.

Gastric Damage and Cancer-Associated Biomarkers in Helicobacter pylori-Infected Children

Helicobacter pylori (H. pylori) is well-known to be involved in gastric carcinogenesis, associated with deregulation of cell proliferation and epigenetic changes in cancer-related genes. H. pylori infection is largely acquired during childhood, persisting long-term in about half of infected individuals, a subset of whom will go on to develop peptic ulcer disease and eventually gastric cancer, however, the sequence of events leading to disease is not completely understood. Knowledge on carcinogenesis and gastric damage-related biomarkers is abundant in adult populations, but scarce in children. We performed an extensive literature review focusing on gastric cancer related biomarkers identified in adult populations, which have been detected in children infected with H. pylori. Biomarkers were related to expression levels (RNA or protein) and/or methylation levels (DNA) in gastric tissue or blood of infected children as compared to non-infected controls. In this review, we identified 37 biomarkers of which 24 are over expressed, three are under expressed, and ten genes are significantly hypermethylated in H. pylori-infected children compared to healthy controls in at least 1 study. Only four of these biomarkers (pepsinogen I, pepsinogen II, gastrin, and SLC5A8) have been studied in asymptomatically infected children. Importantly, 13 of these biomarkers (β-catenin, C-MYC, GATA-4, DAPK1, CXCL13, DC-SIGN, TIMP3, EGFR, GRIN2B, PIM2, SLC5A8, CDH1, and VCAM-1.) are consistently deregulated in infected children and in adults with gastric cancer. Future studies should be designed to determine the clinical significance of these changes in infection-associated biomarkers in children and their persistence over time. The effect of eradication therapy over these biomarkers in children if proven significant, could lead to modifications in treatment guidelines for younger populations, and eventually promote the development of preventive strategies, such as vaccination, in the near future.

p53, Cyclin-D1, β-catenin, APC and c-myc in Tumor Tissue from Colorectal and Gastric Cancer Patients with Suspected Lynch Syndrome by the Bethesda Criteria

Colorectal cancer (CRC) is one of the most frequent neoplasms worldwide, and up to 15% have a family history. Lynch syndrome (LS) is a hereditary cause of CRC and gastric (GC). Individuals with LS have mutations in mismatch genes repair. p53, cyclin D1, β-catenin, APC and c-myc proteins are involved in the cell cycle and carcinogenesis.

Development and validation of a nomogram for preoperative prediction of lymph node metastasis in early gastric cancer

Background

The status of lymph nodes in early gastric cancer is critical to make further clinical treatment decision, but the prediction of lymph node metastasis remains difficult before operation. This study aimed to develop a nomogram that contained preoperative factors to predict lymph node metastasis in early gastric cancer patients.

Methods

This study analyzed the clinicopathologic features of 823 early gastric cancer patients who underwent gastrectomy retrospectively, among which 596 patients were recruited in the training cohort and 227 patients in the independent validation cohort. Significant risk factors in univariate analysis were further identified to be independent variables in multivariable logistic regression analysis, which were then incorporated in and presented with a nomogram. And internal and external validation curves were plotted to evaluate the discrimination of the nomogram.

Results

Totally, six independent predictors, including the tumor size, macroscopic features, histology differentiation, P53, carbohydrate antigen 19-9, and computed tomography-reported lymph node status, were enrolled in the nomogram. Both the internal validation in the training cohort and the external validation in the validation cohort showed the nomogram had good discriminations, with a C-index of 0.82 (95%CI, 0.78 to 0.86) and 0.77 (95%CI, 0.60 to 0.94) respectively.

Conclusions

Our study developed a new nomogram which contained the most common and significant preoperative risk factors for lymph node metastasis in patients with early gastric cancer. The nomogram can identify early gastric cancer patients with the high probability of lymph node metastasis and help clinicians make more appropriate decisions in clinical practice.

Long noncoding RNA VCAN-AS1 contributes to the progression of gastric cancer via regulating p53 expression

Gastric cancer (GC) is one of the most frequent malignancies worldwide. Long noncoding RNAs (lncRNAs) are found to be largely implicated in various cancers, including GC. However, the function of lncRNA VCAN antisense RNA 1 (VCAN-AS1) in GC remains unclear. Herein, we observed a low level of VCAN-AS1 in normal gastric tissues through NCBI and UCSC, and that VCAN-AS1 upregulation in GC tissues was related to poor prognosis by TCGA. Furthermore, VCAN-AS1 was found markedly enhanced in GC tissues and cell lines, while its upregulation was related with clinical outcomes of GC patients. Besides this, silencing VCAN-AS1 represses cell proliferation, migration, and invasion but enhances apoptosis. More important, we discovered that VCAN-AS1 expression was negatively correlated with wild-type p53 levels in GC tissues and that p53 was negatively modulated by VCAN-AS1 in GC cells. Furthermore, p53 suppression reversed the repression of VCAN-AS1 silence on the biological processes of AGS cells. Intriguingly, we identified that both VCAN-AS1 and TP53 can bind with eIF4A3, one of the core proteins in the exon junction complex. Also, we confirmed that VCAN-AS1 negatively regulates TP53 expression by competitively binding with eIF4A3. Our findings disclosed that VCAN-AS1 contributes to GC progression through interacting with eIF4A3 to downregulate TP53 expression, indicating that VCAN-AS1 is a novel therapeutic strategy for GC treatment.

High expression of ALPPL2 is associated with poor prognosis in gastric cancer

Alkaline phosphatase placental-like 2 (ALPPL2) is a member of the ALPP alkaline phosphatase family and is reported to be associated with the growth of some tumors. Gastric cancer is one of the most common cancers worldwide. We previously identified a distinct expression pattern of ALPPL2 between gastric cancer and adjacent normal tissues. In this study, we examined the expression of ALPPL2 in gastric adenocarcinoma and its ability to predict prognosis. We used bioinformatics analysis and immunohistochemistry to examine the expression pattern of ALPPL2 and analyzed the associations between ALPPL2 level and perioperative characteristics and the prognosis of gastric adenocarcinoma patients by Kaplan-Meier plotter analysis. Our results indicated that the expression of ALPPL2 was significantly increased in gastric adenocarcinoma (P < .01) and was an independent factor (P < .05) that could provide reliable prognostic information on gastric adenocarcinoma patients. High expression of ALPPL2 was associated with advanced TNM stage (P < .05) and high HER-2 expression (P < .01). Our study suggests that ALPPL2 has the potential to reveal prognostic information on gastric cancer.

Incorporation of p-53 mutation status and Ki-67 proliferating index in classifying Her2-neu positive gastric adenocarcinoma

Her2-neu overexpression has a pathogenetic, therapeutic and a controversial prognostic role in gastric cancer. p-53 mutation status and Ki-67 proliferation index are established prognostic markers in many tumors. In this study we evaluated p-53 and Ki-67 in relation to Her2-neu positive and negative gastric adenocarcinoma (GA). This cross-sectional study was carried out at King Fahd Hospital of Imam Abdulrahman bin Faisal University. Fifty cases of GA were retrieved from pathology archives. Clinico-pathological parameters were evaluated. Immunohistochemical protein analysis for Her2-neu, Ki-67 and p-53 was carried out. Fluorescent in situ hybridization (FISH) analysis was done for Her2-neu positive cases showing 2+ immunoexpression. Frequency of Ki-67 and p-53 positivity in Her2-neu positive cases was calculated and compared with those in Her2-neu negative cases. Correlation of clinicopatological parameters with Her2 positive and negative cases, p-53 mutation status and Ki-67 proliferation index was carried out. Her2-neu overexpression was present in 12% (n = 6) cases. A high Ki-67 was seen predominantly in Her2-neu positive cases (83%, n = 5). Her2-neu negative cases (n = 44) showed moderate (31.88%, n = 14) to low (34%, n = 15) Ki-67. Diffuse p-53 positivity was seen predominantly in Her2-neu positive cases (33.33%, n = 2). Focal p-53 was seen mainly in Her2-neu negative cases 56.8% (n = 25). Negative p-53 was seen to be independent of Her2-neu status. Her2-neu positivity is strongly associated with diffuse p-53 mutation status and high Ki-67 proliferation. Her 2-neu negative status is associated with focal p-53 positivity and low to moderate Ki-67 proliferation index. Such stratifications in prognostic markers could not only be predictive in patient's prognostics but could also form a basis of molecular classification of gastric cancer.

Estrogen-related receptor gamma functions as a tumor suppressor in gastric cancer

The principle factors underlying gastric cancer (GC) development and outcomes are not well characterized resulting in a paucity of validated therapeutic targets. To identify potential molecular targets, we analyze gene expression data from GC patients and identify the nuclear receptor ESRRG as a candidate tumor suppressor. ESRRG expression is decreased in GC and is a predictor of a poor clinical outcome. Importantly, ESRRG suppresses GC cell growth and tumorigenesis. Gene expression profiling suggests that ESRRG antagonizes Wnt signaling via the suppression of TCF4/LEF1 binding to the CCND1 promoter. Indeed, ESRRG levels are found to be inversely correlated with Wnt signaling-associated genes in GC patients. Strikingly, the ESRRG agonist DY131 suppresses cancer growth and represses the expression of Wnt signaling genes. Our present findings thus demonstrate that ESRRG functions as a negative regulator of the Wnt signaling pathway in GC and is a potential therapeutic target for this cancer.

miR-135a inhibits tumor metastasis and angiogenesis by targeting FAK pathway

Tumor metastasis has been the major cause of recurrence and death in patients with gastric cancer. Here, we find miR-135a has a decreased expression in the metastatic cell lines compared with its parental cell lines by analyzing microRNA array. Further results show that miR-135a is downregulated in the majority of human gastric cancer tissues and cell lines. Decreased expression of miR-135a is associated with TNM stage and poor survival. Besides, regaining miR-135a in gastric cancer cells obviously inhibits tumor growth, migration, invasion and angiogenesis by targeting focal adhesion kinase (FAK) pathway. Bioinformatics analysis and molecular experiments further prove that miR-135a is a novel downstream gene of tumor suppressor p53. Blocking FAK with its inhibitor can also enhance miR-135a expression through inducing p53. In summary, this study reveals the expression and function of miR-135a in gastric cancer and uncovers a novel regulatory mechanism of miR-135a.

Downregulation of the long non-coding RNA taurine-upregulated gene 1 inhibits glioma cell proliferation and invasion and promotes apoptosis

Expression of the long non-coding RNA taurine-upregulated gene 1 (TUG1) is associated with various aggressive tumors. The present study aimed to investigate the biological function of TUG1 in regulating apoptosis, proliferation, invasion and cell cycle distribution in human glioma U251 cells. Lentivirus-mediated TUG1-specific microRNA was transfected into U251 cells to abrogate the expression of TUG1. Flow cytometry analysis was used to examine the cell cycle distribution and apoptosis of U251 cells. Cellular proliferation was examined using Cell Counting Kit-8 (CCK-8) assays and invasion was examined by Transwell assays. The apoptotic rate of cells in the TUG1-knockdown group was significantly higher than in the negative control (NC) group (11.58 vs. 9.14%, P<0.01). CCK-8 assay data demonstrated that the proliferative ability of cells within the TUG1-knockdown group was lower compared with that of the NC group. A Transwell invasion assay was performed, which revealed that the number of invaded cells from the TUG1-knockdown group was the less compared with that of the NC group. In addition, the G₀/G₁ phase population was significantly increased within the treated group (44.85 vs. 38.45%, P<0.01), as measured by flow cytometry. The present study demonstrated that the downregulation of TUG1 may inhibit proliferation and invasion, and promote glioma U251 cell apoptosis. In addition, knockdown of TUG1 may have an effect on cell cycle arrest. The data presented in the current study indicated that TUG1 may be a novel therapeutic target for glioma.

Clinical Significance of p53 Protein Expression, Beta-catenin Expression and HER2 Expression for Epstein-Barr Virus-associated Gastric Cancer

This study assessed the expression of the p53 protein, beta-catenin, and HER2 and their prognostic implications in patients with EBV-associated gastric cancer (EBVaGC). After reviewing 1318 consecutive cases of surgically resected or endoscopic submucosal dissected gastric cancers, 117 patients were identified as EBV-positive using EBV-encoded RNA in-situ hybridization. The immunohistochemistry results were interpreted as follows: strong p53 nuclear expression in at least 50% of tumor nuclei was interpreted as a positive result, strong beta-catenin expression in at least 10% of cytoplasmic nuclei was interpreted as a positive result, and moderate or strong complete or basolateral membrane staining in 10% of tumor cells was interpreted as a positive result for HER2. Immunohistochemical staining for p53 was performed on tumor tissue from 105 patients, among whom 25 (23.8%) tested positive. Meanwhile, beta-catenin expression was positive in 10 patients (17.5%) and HER2 expression was positive in 8 patients (6.8%). The positive expression of p53 was significantly associated with a high T stage (p=0.006). More patients with lymph node metastasis were p53-positive (p=0.013). In the univariate analysis, the p53-positive patients showed significantly decreased disease-free survival (DFS) when compared with the p53-negative patients (p=0.022), although the p53 status was only marginally associated with overall survival (OS) (p=0.080). However, p53 expression showed no prognostic significance on DFS in the multivariate analysis. Moreover, beta-catenin and HER2 showed no association with DFS and OS in the survival analysis. The current study found a significant correlation between p53 expression and tumor progression and lymph node metastases in patients with EBVaGC.

Prognostic value and clinicopathological significance of proliferating cell nuclear antigen expression in gastric cancer: a systematic review and meta-analysis

BACKGROUND

The prognostic significance of proliferating cell nuclear antigen (PCNA) expression in gastric cancer has long been assessed, yet results remain controversial. Therefore, we performed a meta-analysis to assess the prognostic value and clinicopathological significance of PCNA in gastric cancer.

METHODS

A systematic literature search of PubMed, EMBASE, and the Cochrane Library databases was conducted. Summary odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to investigate the correlations between PCNA expression and clinicopathological features, overall survival (OS), and disease-free survival (DFS).

RESULTS

A total of 19 studies involving 2,852 participants were included in our analysis. The pooled HR indicated that high PCNA expression was significantly associated with poor OS (HR 1.66, 95% CI 1.32-2.08) and DFS (HR 1.81, 95% CI 1.40-2.36). Subgroup analysis revealed that the association between PCNA and OS was also significant in Asian and European patients. In addition, the pooled ORs showed that high PCNA expression was significantly associated with deeper tumor invasion (OR 2.37, 95% CI 1.71-3.27), lymph node metastasis (OR 2.49, 95% CI 1.85-3.35), and advanced stage cancer (OR 1.89, 95% CI 1.36-2.63).

CONCLUSION

Our meta-analysis indicates that high PCNA expression might be a prognosticator of poor survival and a promising therapeutic target for gastric cancer patients.

Poorly Differentiated Medullary Phenotype Predicts Poor Survival in Early Lymph Node-Negative Gastro-Esophageal Adenocarcinomas

BACKGROUND

5-year survival rate in patients with early adenocarcinoma of the gastro-esophageal junction or stomach (AGE/S) in Caucasian patients is reported to be 60-80%. We aimed to identify prognostic markers for patients with UICC-I without lymph-node involvement (N0).

METHODS

Clinical data and tissue specimen from patients with AGE/S stage UICC-I-N0, treated by surgery only, were collected retrospectively. Tumor size, lymphatic vessel or vein invasion, grading, classification systems (WHO, Lauren, Ming), expression of BAX, BCL-2, CDX2, Cyclin E, E-cadherin, Ki-67, TP53, TP21, SHH, Survivin, HIF1A, TROP2 and mismatch repair deficiency were analyzed using tissue microarrays and correlated with overall and tumor related survival.

RESULTS

129 patients (48 female) with a mean follow-up of 129.1 months were identified. 5-year overall survival was 83.9%, 5-year tumor related survival was 95.1%. Poorly differentiated medullary cancer subtypes (p<0.001) and positive vein invasion (p<0.001) were identified as risk factors for decreased overall-and tumor related survival. Ki-67 (p = 0.012) and TP53 mutation (p = 0.044) were the only immunohistochemical markers associated with worse overall survival but did not reach significance for decreased tumor related survival.

CONCLUSION

In the presented study patients with AGE/S in stage UICC-I-N0 had a better prognosis as previously reported for Caucasian patients. Poorly differentiated medullary subtype was associated with reduced survival and should be considered when studying prognosis in these patients.

HER3 over-expression and overall survival in gastrointestinal cancers

Published studies on the association between human epidermal factor receptor 3 (HER3) expression and overall survival (OS) in gastrointestinal cancers have yielded conflicting results. The aim of this study was to explore the association of HER3 over-expression with OS in gastrointestinal cancers. A systematic search was performed through Medline/PubMed, Embase, Science Direct and Elsevier. The summary odds ratio (OR) with 95% confidence interval (CI) was calculated to estimate the strength of the association. Overall, we observed that HER3 over-expression was associated with worse OS at five years (OR = 1.38, 95% CI: 1.04-1.82); however, HER3 over-expression was not associated with worse OS at three years (OR = 1.33, 95% CI: 0.97-1.84). The cumulative meta-analysis showed similar results. In subgroup analyses by tumor type, HER3 over-expression in gastric cancers was associated with worse OS at both three years (OR = 1.69, 95% CI: 1.28-2.25) and five years (OR = 1.74, 95% CI: 1.26-2.41). In conclusion, our results suggest that HER3 over-expression may be associated with worse overall survival in gastric cancers. Well-designed studies with a large sample size are required to further confirm our findings.

Prognostic Value and Clinicopathological Significance of p-stat3 Among Gastric Carcinoma Patients: A Systematic Review and Meta-Analysis

The overexpression of phosphorylated signal transducer and activator of transcription 3 (p-stat3) was detected in a variety of human tumors. The published studies on p-stat3 expression among gastric carcinoma patients remain controversial.In order to clarify the prognosis value of p-stat3 with overall survival and its association with clinicopathological characteristics in gastric carcinoma, we performed a systematic review and meta-analysis.Eligible studies were retrieved by searching PubMed, Embase, Cochrane library, and Chinese biomedical literature service system databases.Studies described the association between p-stat3 expression and clinicopathological characteristics and overall survival in gastric carcinoma patients; p-stat3 expression was detected by immunohistochemistry (IHC).Odds ratio (OR) and hazard ratio (HR) were considered as a measure of evaluating the association in meta-analysis; I was used to assess the heterogeneity across studies; publication bias was assessed with funnel plot, Egger test, and Begg test.Twenty-three studies including 2872 patients which evaluated the p-stat3 expression by IHC in gastric carcinoma were included. The pooled HR (HR = 2.02, 95% CI: 1.49-2.73, P < 0.00001) indicated that the increased p-stat3 expression was significantly associated with poor overall survival. In addition, when we investigated the association between p-stat3 overexpression and clinicopathological characteristics of gastric carcinoma, we found that the increased p-stat3 expression was significantly associated with tumor differentiation (poorly vs well-moderately: OR = 3.70, 95% CI: 1.98-6.93, P < 0.0001) and lymph node metastasis (present vs absent: OR = 2.40, 95% CI: 1.28-4.50, P = 0.007).The different type of primary antibody was used; the assessment methods of p-stat3 positive expression were defined differently; the locations of p-stat3 expression were different; the method of extrapolating HR from Kaplan-Meier survival curves did seem to be less reliable than when HR was extracted directly from literatures; sample sizes, the age of patients, and the follow-up durations are different.In conclusion, our meta-analysis indicates that the increased p-stat3 expression may be not only predict poor prognosis, but also be associated with worse tumor differentiation and lymph node metastasis in patients with gastric carcinoma.

Histopathological, Molecular, and Genetic Profile of Hereditary Diffuse Gastric Cancer: Current Knowledge and Challenges for the Future

Familial clustering is seen in 10 % of gastric cancer cases and approximately 1-3 % of gastric cancer arises in the setting of hereditary diffuse gastric cancer (HDGC). In families with HDGC, gastric cancer presents at young age. HDGC is predominantly caused by germline mutations in CDH1 and in a minority by mutations in other genes, including CTNNA1. Early stage HDGC is characterized by a few, up to dozens of intramucosal foci of signet ring cell carcinoma and its precursor lesions. These include in situ signet ring cell carcinoma and pagetoid spread of signet ring cells. Advanced HDGC presents as poorly cohesive/diffuse type carcinoma, normally with very few typical signet ring cells, and has a poor prognosis. Currently, it is unknown which factors drive the progression towards aggressive disease, but it is clear that most intramucosal lesions will not have such progression.Immunohistochemical profile of early and advanced HDGC is often characterized by abnormal E-cadherin immunoexpression, including absent or reduced membranous expression, as well as "dotted" or cytoplasmic expression. However, membranous expression of E-cadherin does not exclude HDGC. Intramucosal HDGC (pT1a) presents with an "indolent" phenotype, characterized by typical signet ring cells without immunoexpression of Ki-67 and p53, while advanced carcinomas (pT > 1) display an "aggressive" phenotype with pleomorphic cells, that are immunoreactive for Ki-67 and p53. These features show that the IHC profile is different between intramucosal and more advanced HDGC, providing evidence of phenotypic heterogeneity, and may help to define predictive biomarkers of progression from indolent to aggressive, widely invasive carcinomas.

The Role of p53 Gene in Cervical Carcinogenesis

AIM

To investigate the role of p53 gene in cervical carcinogenesis.

MATERIALS AND METHODS

A total 50 cases and controls were taken after setting exclusion criteria. Venous blood (3 ml) samples were collected in sterile EDTA sterile vials. Both punch biopsy of cervical growth in cases and biopsy from cervix after hysterectomy in controls were performed. Genomic DNA was extracted from tissue and blood using standard protocol of Miller et al. 1994 using chloroform-phenol method. Gene was amplified using specific forward and reverse primers and p53 gene expressions were studied. The present study of p53 gene regulation analyzed the expression of 279-bp bands on 1.5 agarose gel.

OBSERVATIONS

Out of the total 50 samples of cases and controls, we were able to isolate DNA from 38 cases and 28 controls in blood and in 22 cases and 22 controls in tissue. In cases of carcinoma cervix, p53 expression is either downregulated or absent in 71.06 % of cases compared to 50 % of controls in blood and 72.73 % of cases compared to 59.09 % of controls in tissue, but these figures were not statistically significant (p = 0.67 and p = 0.167, respectively). p53 positivity rate was only in 27.78 % of squamous cell cancer and 50 % of adenocarcinoma. Three out of nine patients (33.3 %) with L.N. positive status have p53 gene positivity, whereas 23 % (3 out of 13) with L.N. negative status have p53 gene positivity, which is not significantly associated. In our study, p53 overexpression increases with the various stages of cervical cancer.

CONCLUSION

In our study, we found that there is the increased frequency of upregulation or overexpression of p53 gene in control in both blood (50 %) and tissue (40.9 %), but this association is statistically nonsignificant. In the present study, there is a lack of relationship between p53 overexpression and prognosis in the cervical cancer patients. However, our study lacked larger sample size which otherwise would have been able to lend support to truly significant findings through much larger combined and comparative datasets.

Expression, correlation, and prognostic value of TRAF2 and TRAF4 expression in malignant plural effusion cells in human breast cancer

BACKGROUND

TRAF2 and TRAF4, members of the tumor necrosis factor receptor- associated factor family of intracellular signal transduction proteins, are associated with breast cancer progression and metastasis.

METHODS

We collected malignant serous effusion cells from the patients with breast cancer (n = 46). Cell blocks prepared from plural effusions (n = 46) and primary breast cancer (n = 50), lymph node metastases (n = 50), and normal breast tissue specimens (n = 30). The immunohistochemistry was performed for the detection of TRAF2 and TRAF4 expression with the correlation of their expression with clinicopathological parameters and survival rate analyzed.

RESULTS

Compared with normal breast tissues, TRAF2 expression was upregulated, and nuclear TRAF4 expression was downregulated in malignant pleural effusion cells, primary tumors, and lymph node metastases (P < 0.05). Multivariate analysis revealed TRAF2 expression in pleural effusions was associated with the molecular/pathological type, venous invasion, and lymph node metastasis, while nuclear TRAF4 expression was associated with age, tumor size, venous invasion, and lymph node metastasis, clinical staging, molecular/pathological subtype and p53 status (P < 0.05). There was a significant positive correlation between TRAF2 and TRAF4 expression levels in malignant pleural effusion cells (r = 0.937; P < 0.01). Kaplan-Meire analysis demonstrated a close correlation of TRAF2 and TRAF4 expression in malignant pleural effusion cells with cumulative overall survival (P < 0.05).

CONCLUSION

TRAF2 and nuclear TRAF4 expression in malignant pleural effusion cells may represent potential prognostic factors and biomarkers of invasion and metastasis in breast cancer.