Early-onset gastric cancers have a different molecular expression profile than conventional gastric cancers

Trends, clinicopathological features, surgical treatment patterns and prognoses of early-onset versus late-onset gastric cancer: A retrospective cohort study

INTRODUCTION

This study investigates the differences between early-onset gastric carcinoma (EOGC) and late-onset gastric carcinoma (LOGC) by examining trends, demographics, clinical and molecular features, treatments, and outcomes at a leading cancer center in China.

OBJECTIVES

To delineate the distinctions between EOGC and LOGC in terms of patient characteristics, disease progression, and treatment outcomes, and to suggest appropriate screening strategies.

METHODS

We analyzed 18,877 gastric carcinoma cases treated at Fudan University Shanghai Cancer Center (FUSCC) from 2000 to 2022. Descriptive statistics were performed using IBM SPSS. Survival rates were assessed via the Kaplan-Meier method and log-rank test, while COX regression analysis identified factors affecting disease-free survival (DFS) and overall survival (OS).

RESULTS

The average age of gastric cancer diagnosis has increased slightly since 2000, with a steady rise in both EOGC and LOGC cases, though EOGC's proportion has slightly decreased. EOGC had a higher proportion of female patients and was more common in the gastric body and antrum pylorus. EOGC cases showed lower levels of cancer biomarkers, HER2 expression, vascular and lymphatic invasion, and lower differentiation and invasion depth. They also exhibited more advanced N and TNM staging, Borrmann IV type, and low adhesive carcinoma. EOGC underwent more extensive D2 lymphadenectomy and neoadjuvant chemotherapy. There were no significant differences in Claudin18.2 and MMR protein status between EOGC and LOGC. EOGC had higher rates of ovarian and peritoneal metastases, with a better early prognosis but faster late-stage progression.

CONCLUSION

EOGC and LOGC cases have increased over the past two decades. EOGC presents unique clinical and pathological features, requiring thorough surgical treatment and has a better early prognosis but more rapid late-stage progression. Enhanced screening for younger adults is recommended to address the rising EOGC trend.

Expressions of HuR, Methyl-HuR and Phospho-HuR in Endometrial Endometrioid Adenocarcinoma Are Associated with Clinical Features

HuR regulates cytoplasmic mRNA stability and translatability, with its expression correlating with adverse outcomes in various cancers. This study aimed to assess the prognostic value and pro-oncogenic properties of HuR and its post-translational isoforms methyl-HuR and phospho-HuR in endometrial adenocarcinoma. Examining 89 endometrioid adenocarcinomas, we analyzed the relationship between HuR nuclear or cytoplasmic immunostaining, tumor-cell proliferation, and patient survival. HuR cytoplasmic expression was significantly increased in grade 3 vs. grade 1 adenocarcinomas (p < 0.001), correlating with worse overall survival (OS) (p = 0.02). Methyl-HuR cytoplasmic expression significantly decreased in grade 3 vs. grade 1 adenocarcinomas (p < 0.001) and correlated with better OS (p = 0.002). Phospho-HuR nuclear expression significantly decreased in grade 3 vs. grade 1 adenocarcinomas (p < 0.001) and non-significantly correlated with increased OS (p = 0.06). Cytoplasmic HuR expression strongly correlated with proliferation markers MCM6 (rho = 0.59 and p < 0.001) and Ki67 (rho = 0.49 and p < 0.001). Conversely, these latter inversely correlated with cytoplasmic methyl-HuR and nuclear phospho-HuR. Cytoplasmic HuR expression is a poor prognosis marker in endometrioid endometrial adenocarcinoma, while cytoplasmic methyl-HuR and nuclear phosphoHuR expressions are markers of better prognosis. This study highlights HuR as a promising potential therapeutic target, especially in treatment-resistant tumors, though further research is needed to understand the mechanisms regulating HuR subcellular localization and post-translational modifications.

Biological and clinical implications of early-onset cancers: A unique subtype

In recent years, the incidence of cancers is continuously increasing in young adults. Early-onset cancer (EOC) is usually defined as patients with cancers under the age of 50, and may represent a unique subgroup due to its special disease features. Overall, EOCs often initiate at a young age, present as a better physical performance but high degree of malignancy. EOCs also share common epidemiological and hereditary risk factors. In this review, we discuss several representative EOCs which were well studied previously. By revealing their clinical and molecular similarities and differences, we consider the group of EOCs as a unique subtype compared to ordinary cancers. In consideration of EOC as a rising threat to human health, more researches on molecular mechanisms, and large-scale, prospective clinical trials should be carried out to further translate into improved outcomes.

Multi‑institutional development and validation of a nomogram to predict prognosis of early-onset gastric cancer patients

Background

Early-onset gastric cancer (EOGC, ≤45 years old) is characterized with increasing incidence and more malignant phenotypes compared with late-onset gastric cancer, which exhibits remarkable immune cell infiltration and is potential immunotherapeutic population. Till now, restricted survival information of EOGC is available due to limited case numbers. This study established a novel nomogram to help evaluate cancer-specific survival (CSS) of EOGC patients who underwent gastrectomy, and may provide evidence for predicting patients’ survival.

Methods

We retrospectively enrolled a cohort containing 555 EOGC cases from five independent medical centers in China, among which 388 cases were randomly selected into a training set while the other 167 cases were assigned into the internal validation set. Asian or Pacific Islander (API) patients diagnosed with EOGC during 1975-2016 were retrieved from the SEER database (n=299) and utilized as the external validation cohort. Univariate and multivariate analyses were conducted to test prognostic significances of clinicopathological factors in the training set. Accordingly, two survival nomogram models were established and compared by concordance index (C-index), calibration curve, receiver operating characteristics (ROC) curves and decision curve analyses (DCA).

Results

The 5-year CSS rate of training cohort was 61.3% with a median survival time as 97.2 months. High consistency was observed on calibration curves in all three cohorts. Preferred nomogram was selected due to its better performance on ROC and DCA results. Accordingly, a novel predicative risk model was introduced to better stratify high-risk EOGC patients with low-risk patients. In brief, the 5-year CSS rates for low-risk groups were 92.9% in training set, 83.1% in internal validation set, 89.9% in combined NQSQS cohort, and 85.3% in SEER-API cohort. In contrast, the 5-year CSS rates decreased to 38.5%, 44.3%, 40.5%, and 36.9% in the high-risk groups of the four cohorts above, respectively. The significant survival difference between high-risk group (HRG) and low-risk group (LRG) indicated the precise accuracy of our risk model. Furthermore, the risk model was validated in patients with different TNM stages, respectively. Finally, an EOGC web-based survival calculator was established with public access, which can help predict prognosis.

Conclusions

Our data provided a precise nomogram on predicting CSS of EOGC patients with potential clinical applicability.

Sex and gender disparities in patients with advanced gastroesophageal adenocarcinoma: data from the AGAMENON-SEOM registry

Background

Recommendations for research articles include the use of the term sex when reporting biological factors and gender for identities or psychosocial or cultural factors. There is an increasing awareness of incorporating the effect of sex and gender on cancer outcomes. Thus, these types of analyses for advanced gastroesophageal adenocarcinoma are relevant.

Patients and methods

Patients with advanced gastroesophageal adenocarcinoma from the Spanish AGAMENON-SEOM registry treated with first-line combination chemotherapy were selected. Epidemiology, characteristics of the disease, treatment selection, and results were examined according to sex.

Results

This analysis included 3274 advanced gastroesophageal adenocarcinoma patients treated with combination chemotherapy between 2008 and 2021: 2313 (70.7%) men and 961 (29.3%) women. Tumors in females were more frequently HER2-negative (67.8% versus 60.8%; P < 0.0001), grade 3 (45.4% versus 36.8%; P < 0.001), diffuse (43.3% versus 26.5%; P < 0.0001), and signet ring cell histology (40.5 versus 23.9%; P < 0.0001). Peritoneal spread was more common in women (58.6% versus 38.9%; P < 0.0001), while liver burden was lower (58.9% versus 71.1%; P < 0.0001). There were no significant differences in treatment recommendation. Treatment doses, density, and duration were comparable between sexes. Women experienced more diarrhea (46% versus 37%; P < 0.0001), neutropenia (51% versus 43%; P < 0.0001), and anemia (62% versus 57%; P < 0.0001). After a median 59.6-month follow-up [95% confidence interval (CI) 54.5-70.8], there were no statistically significant differences between the sexes in progression-free survival [6.21 months (95% CI 5.8-6.5 months) versus 6.08 months (95% CI 5.8-6.3 months); log-rank test, χ² = 0.1, 1 df, P = 0.8] or in overall survival [10.6 months (95% CI 9.8-11.1 months) versus 10.9 months (95% CI 10.4-11.4 months); log-rank test: χ² = 0.6, 1 df, P = 0.5].

Conclusion

This sex analysis of patients with advanced gastroesophageal adenocarcinoma from the AGAMENON-SEOM registry receiving first-line polychemotherapy found no differences in survival. Although women had worse prognostic histopathology, metastatic disease pattern, and greater toxicity, treatment allocation and compliance were equivalent.

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Sex and gender are determinants of health inequalities and may affect treatments, tolerability, and therapeutic outcomes.

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According to sex, subtle biological and clinical differences exist in advanced gastroesophageal adenocarcinoma.

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Women with advanced gastroesophageal adenocarcinoma experience greater toxicity with therapeutic results comparable with men.

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Stratification and analysis by sex in studies of gastroesophageal adenocarcinoma should be considered.

Proportion of Early-Onset Gastric and Esophagus Cancers Has Changed Over Time With Disproportionate Impact on Black and Hispanic Patients

PURPOSE

The proportion of gastroesophageal junction adenocarcinoma is increasing. This study evaluated trends in early-onset gastric and esophageal cancers and compared socioeconomic and clinical characteristics between early-onset versus late-onset disease.

MATERIALS AND METHODS

We included all patients with gastric and esophageal cancer from 2004 to 2015 from the National Cancer Database. Patients were categorized by age < 50, 50-69, and ≥ 70 years. Differences in pathologic and socioeconomic factors between early-onset and late-onset cancers were assessed by using chi-square test. The effects of demographic and socioeconomic factors on overall survival (OS) were assessed using Cox models.

RESULTS

The proportion of patients with early-onset gastric cancer increased from 23.9% in 2004-2006 to 26.2% in 2013-2015, whereas the proportion of early-onset esophageal cancer decreased from 27.3% in 2004-2006 to 23.1% in 2013-2015. For both malignancies, the early-onset group was more likely to be Black or Hispanic and more likely to be diagnosed with stage IV cancer. Black patients had the worst median OS in both malignancies. In gastric cancer, within the Black patient group, patients experienced worse OS if they had government insurance versus private insurance (hazard ratio 1.2; 95% CI, 1.1 to 1.3; P value < .0001) or if they were in the lowest community median income category versus the highest category (hazard ratio 1.2; 95% CI, 1.1 to 1.3; P value < .0001).

CONCLUSION

Early-onset gastric cancer is increasing, whereas early-onset esophageal cancer is declining. Early-onset gastric cancer disproportionately affects non-White patients, particularly Hispanic patients. Black patients have worse outcomes compared with other races for both gastric and esophageal cancer.

Polymorphisms of an oncogenic gene, mesothelin, predict the risk and prognosis of gastric cancer in a Chinese Han population

Mesothelin (MSLN) is a cell surface protein associated with tumor invasion and metastasis. This study aims to explore the biological function of MSLN in gastric cancer and to evaluate the association of MSLN polymorphism (rs3764247, rs3764246, rs12597489, rs1057147, rs3765319) with the risk and prognosis of gastric cancer. Small interfering RNA (siRNA) transfection and MSLN overexpression were performed in human gastric cancer cell lines, respectively. The proliferation of tumor cells was evaluated by Cell counting kit 8(CCK-8) and colony formation assay. Wound healing assay and transwell assay were used to elucidate gastric cancer cell migration and invasion rates. We conducted a case-control study involving 860 patients with gastric cancer and 870 controls. All mutation sites were genotyped by PCR-LDR sequencing. First, our study revealed the cancer-promoting role of MSLN in gastric cancer. Second, we also demonstrated that rs3764247 and rs3764246 were associated with a reduced risk of gastric cancer (OR = 0.83, p = 0.010; OR = 0.84, p = 0.011; respectively). The clinicopathological analysis further showed that rs3764247 was closely related to T stage, vascular infiltration, and HER2 expression. In addition, in the survival analysis of 392 patients with gastric cancer, patients with rs3764247 CC genotype had poorer survival than patients with AA + AC genotype after adjusting for age, sex, TNM stage, and Lauren classification (HR = 2.07, p = 0.029). Our findings indicated that MSLN could be an oncogene whose polymorphisms were closely related to the risk and prognosis of gastric cancer.

Higher Lymph Node Metastasis Rate and Poorer Prognosis of Intestinal-Type Gastric Cancer Compared to Diffuse-Type Gastric Cancer in Early-Onset Early-Stage Gastric Cancer: A Retrospective Study

Background: The incidence of early-onset gastric cancer (GC) that was diagnosed at <50 years is increasing, but there is a knowledge gap on early-onset early-stage GC (EEGC) that was defined as early-onset GC limited to the mucosa or submucosa. Therefore, we comprehensively analysed the clinical features based on Lauren type.

Methods: Logistic and Cox analyses were used to investigate risk factors for lymph node metastasis (LNM) and prognosis, respectively. Propensity score matching (PSM) was used to adjust confounding factors. Protein mass spectrometry analysis was used to explore the molecular mechanism of LNM.

Result: Our study included 581 patients with EEGC from the Surveillance, Epidemiology, and End Results (SEER) database and 226 patients with EEGC from our own centre. We identified intestinal type, T1b stage, and tumour size (>3 cm) as risk factors for LNM using SEER and our own data. We also found that the prognosis of patients with intestinal-type EEGC was poorer than patients with diffuse-type EEGC, and T1b stage and positive LNM were hazard factors for survival. After analysing the expression of proteins between positive and negative LNM in the intestinal or diffuse type, we found no similar proteins between these groups. The differentially expressed genes (DEGs) in the intestinal type functioned as epithelial cell signalling in Helicobacter pylori. The DEGs in the diffuse type functioned in the tricarboxylic acid cycle (TCA cycle) and oxidative phosphorylation.

Conclusion: For EEGC, our study was the first report to demonstrate that the intestinal type was a risk factor for LNM and survival compared to the diffuse type, and the oncogenic expression promoting the occurrence of LNM was different. These findings suggest that clinicians should pay more attention to intestinal-type EEGC than diffuse-type EEGC.

Identification of Novel Alternative Splicing Events Associated With Tumorigenesis, Protein Modification, and Immune Microenvironment in Early-Onset Gastric Cancer

Background

Alternative splicing (AS), e.g. the tandem alternative polyadenylation (TAPA), has emerged as major post-transcriptional modification events in human disease. However, the roles of the AS and TAPA in early-onset gastric cancer (EOGC) have not been revealed.

Methods

The global AS profiles of 80 EOGC patients were analyzed. The EOGC-specific AS events (ESASs) were identified in both the EOGC and adjacent non-tumor tissues. The functional enrichment analysis, Splicing network, Alternative Polyadenylation (APA) core factor network, and cell abundancy analysis were performed. Furthermore, the landscapes of the AS events in the varied subtypes of the EOGC patients were evaluated.

Results

Overall, 66,075 AS events and 267 ESASs were identified in the EOGC. Furthermore, 4809 genes and 6152 gene isoforms were found to be aberrantly expressed in the EOGC. The Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analyses showed that the significant pathway alterations might exist in these AS events, genes, and gene isoforms. Moreover, the Protein-protein interaction (PPI) network analysis revealed that the UBC, NEK2, EPHB2, and DCTN1 genes were the hub genes in the AS events in the EOGC. The immune cell infiltration analysis indicated a correlation between the AS events and the cancer immune microenvironment. The distribution of the AS events in varied EOGC subtypes, protein phosphorylation and glycosylation was uneven.

Conclusion

The study highlighted the vital roles of the AS in the EOGC, including modulating the specific protein modification and reshaping the cancer immune microenvironment, and yielded new insights into the diagnosis of the EOGC as well as cancer treatment.

Genetic polymorphisms of Cathepsin B are associated with gastric cancer risk and prognosis in a Chinese population

BACKGROUND

Genetic polymorphisms are believed to represent a key aspect of predisposition to gastric cancer (GC). Therefore, considering the important role of Cathepsin B (CTSB) in promoting cancer onset and development, it could be very worthful to explore the function of CTSB-related genetic polymorphisms in GC.

OBJECTIVE

In this study, we investigated the correlation of CTSB-related polymorphisms (rs9009A>T, rs6731T>C, rs1293303G>C, rs1874547C>T, rs3779659C>T, rs17814426C>T and rs148669985C>T) with GC risk and prognosis in a case-control study of 994 cases and 1000 controls.

METHODS

All tag single nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction-ligase detection reaction (PCR-LDR) sequencing technology.

RESULTS

The results indicated rs9009, rs6731 and rs17814426 correlated with decreased risks of GC (HR = 0.97, p< 0.001; HR = 0.86, P= 0.019; HR = 0.85, P= 0.017; respectively). Stratification analysis further showed rs17814426 variant genotypes correlated with earlier T stage (p= 0.044). In addition, GC patients carrying the C allele of rs6371 had better overall prognosis (HR = 0.62, 95%CI = 0.44-0.88).

CONCLUSION

Our results firstly suggested the importance of CTSB-related polymorphisms on GC which could predict GC risk and prognosis.

Comparative investigation of early-onset gastric cancer

Early-onset gastric cancer (EOGC) is a serious social burden. For patients with EOGC, typically considered as those aged <45 years, the underlying cause of the disease remains unclear. In addition, several misunderstandings of EOGC remain in clinical practice. Upon diagnosis, numerous patients with EOGC are already at an advanced stage (stage IV) of the disease and are unable to benefit from treatment. Moreover, several conclusions and data obtained from different EOGC studies appear to be to contradictory. The literature indicates that the incidence of EOGC is gradually rising, and that EOGC differs from traditional and familial gastric cancer in terms of clinicopathological characteristics. Patients with EOGC typically exhibit low survival rates, poor prognosis, rapid disease progression, a low degree of differentiation (signet-ring cell tumors are common) and rapid lymph node and distant metastasis, among other characteristics. The molecular genetic mechanisms of EOGC are also significantly different from those of traditional gastric cancer. An improved definition of EOCG may provide a reference for clinical diagnosis and treatment, and clear guidelines may serve as a basis for more accurate diagnosis and the development of effective treatment strategies.

Status of CHEK2 and p53 in patients with early-onset and conventional gastric cancer

Gastric cancer (GC) is the fourth most common cause of cancer-associated death. Based on the age at diagnosis, GC is divided into early-onset GC (EOGC; ≤45 years) and conventional GC (CGC; >45 years). Mutations in the cell cycle checkpoint kinase 2 (CHEK2) and TP53 genes are associated with several types of cancer; however, their genetic defects in GC remain poorly understood. The aim of the present study was to determine the subcellular distribution of the CHEK2 protein and its redistribution following DNA damage, to improve the understanding of the DNA damage response. Genetic alterations and patterns of expression of CHEK2 and p53 proteins were investigated to identify potential biological markers and indicators of GC development. Additionally, the affected signaling pathways and their clinical importance in GC development and associated syndromes were investigated. A total of 196 GC samples (89 CGC and 107 EOGC samples) were used in the present study. DNA from 53 samples (18 CGC and 35 EOGC samples) was sequenced using targeted next-generation sequencing technology to identify and compare common and rare mutations associated with GC. Subsequently, the cytoplasmic and nuclear expression levels of CHEK2, phosphorylated (p)-CHEK2 at threonine 68 and p53 in GC tissues were determined via immunohistochemistry. Sequencing resulted in the identification of 63 single nucleotide polymorphisms (SNPs) in the CHEK2 gene amongst 5 different variants, and the intron variant c.319+379A>G was the most common SNP. In the TP53 gene, 57 different alterations were detected amongst 9 variant types, and the missense variant c.215C>G was the most common. Nuclear CHEK2 expression was high in both the EOGC and CGC subtypes. However, the prevalence of cytoplasmic CHEK2 expression (P<0.001) and nuclear p-CHEK2 expression (P=0.011) was significantly higher in CGC compared with in EOGC tissues. There was a statistically significant difference between high and low cytoplasmic CHEK2 expression in patients with p53-positive EOGC compared with in patients with p53-positive CGC (P=0.002). The present study was designed to determine the association between CHEK2 and p53 expression patterns in patients with EOGC and CGC, as well as genetic alterations in the CHEK2 and TP53 genes.

Morphologic and molecular analysis of early-onset gastric cancer

BACKGROUND

Evidence suggests that early-onset gastric cancers are distinct from traditional gastric cancers; however, detailed genomic and morphologic characterization of these cancers has not been performed.

METHODS

Genomic analysis was performed for 81 patients with gastric cancer who were 50 years old or younger; pathology slides were available for 53 of these patients, and they were re-reviewed to perform a morphologic-molecular correlation analysis. The results were compared with corresponding cBioPortal data and The Cancer Genome Atlas (TCGA) analysis, which represent traditional gastric cancers. The TP53 molecular signature was established to determine the pattern of somatic mutational damage. Variants of potential germline origin were also identified from next-generation sequencing data.

RESULTS

A higher rate of CDH1 mutations (22.2% of early-onset gastric cancers vs 11.4% of traditional gastric cancers; P = .0042) but a similar rate of TP53 mutations (63% of early-onset gastric cancers vs 56.6% of traditional gastric cancers; P = .2674) were seen in early-onset cancers in comparison with traditional gastric cancers. The diffuse/mixed types correlated with the TCGA genomically stable type, and the remaining Lauren types correlated with the TCGA chromosomal instability type. Diffuse and indeterminate histologic types (overall survival, 26.25 months for the intestinal type, 20.5 months for the mixed type, 12.62 months for the diffuse type, and 9 months for the indeterminate type; P = .027) and the presence of a CDH1 gene mutation (overall survival, 9 months for mutant CDH1 and 22 months for wild-type CDH1; P = .013) significantly correlated with worse survival. The TP53 gene frequently showed transition mutations (65.5%) involving the CpG sites (49%). Variants of potential germline origin were seen in high-penetrance genes (CDH1 and APC) and moderate-penetrance genes (ATM, NBN, and MUTYH) in 9.9% of cancers.

CONCLUSIONS

Early-onset gastric cancer has distinct genomic alterations, such as CDH1 mutations, but shares with traditional gastric cancers a high frequency of TP53 mutations and the TP53 mutagenic signature. Diffuse and indeterminate histologic types and the presence of a CDH1 mutation are associated with worse overall survival. Endogenous factors leading to cytosine deamination and potential germline alterations in moderate-penetrance cancer susceptibility genes may be implicated in the pathogenesis of these cancers.

Gastric carcinogenesis: a comprehensive review of the angiogenic pathways

Gastric cancer (GC) is undoubtedly one of the most prevalent malignancies worldwide. Since GC is the second leading cause of cancer-related deaths with nearly one million new diagnoses reported every year, there is a need for the development of new, effective treatment strategies of GC. Gastric carcinogenesis is a complex process that is induced by numerous factors and further stimulated by many pro-oncogenic pathways. Angiogenesis is the process of the new blood vessels formation from the already existing ones and it significantly contributes to the progression of gastric tumorigenesis and the growth of the cancerous tissues. The newly formed vessels provide cancer cells with proper nutrition, growth factors, and oxygen supply that are crucial for tumor growth and progression. Tumor-associated vessels differ from the physiological ones both morphologically and functionally. They are usually inefficient and unevenly distributed due to structural transformations. Thus, the development of the angiogenesis inhibitors that possess therapeutic effects has been the main focus of recent studies. Angiogenesis inhibitors mostly affect the vascular endothelial growth factor (VEGF) pathway since it is a major factor that stimulates the pro-angiogenic pathways. The aim of this review was to describe and summarize other promising molecular pathways that might be crucial in further improvements in GC therapies. This article provides an overview of how a meaningful role in tumor progression the angiogenetic process has. Furthermore, this review includes a description of the most important angiogenic factors as well as pathways and their involvement in gastric carcinogenesis.

Analysis of the Incidence and Survival of Gastric Cancer Based on the Lauren Classification: A Large Population-Based Study Using SEER

Background: Limited evidence exists on the incidence of gastric cancer (GC), and contradictory results exist for the prognosis of GC based on the Lauren classification. We analyzed the incidence and survival of GC based on the Lauren classification. Methods: The Surveillance, Epidemiology, and End Results (SEER) database from 1975 through 2015 was used to identify all patients with surgically resected, histologically diagnosed intestinal or diffused-type GC. Propensity score matching was used to analyze the association between the Lauren classification type and prognosis. Results: The trend of total GC incidence showed an obvious decrease (APC = -1.51, 95% CI: -2.31 to -1.01) as well as that of the intestinal type (APC = -1.43, 95% CI: -2.01 to -1.12). However, we found that the relative incidence of the diffused type was increased (APC = 0.6, 95% CI: 0.41-0.82). The trend of the total incidence of GC (APC = -1.31, 95% CI: -1.91 to -1.03) and that of the intestinal type (APC = -1.11, 95% CI: -1.53 to -0.98) was decreased in 40-49-year-olds, but that of the diffused type was increased (APC = 1.5, 95% CI: 1.2-1.72). We found that trends in GC incidence exhibited a similar pattern in the regional and distant stages and showed a decrease from 1975 through 2015. However, the incidence rate of the local stage was increased, with an APC of 0.5 (95% CI: 0.3-0.7). We identified 15,989 GC cases from the SEER database, including 13,852 intestinal-type and 2,138 diffused-type cases. The 1,336 intestinal-type cases were matched with 1,336 diffused-type cases using propensity score matching (PSM), and patients with the diffused type had a better prognosis than patients with the intestinal type (HR = 0.56, 95% CI: 0.45-0.78). However, we found that patients with diffused-type GC had worse survival than patients with intestinal-type GC in the cohort from Renji Hospital (P < 0.001). Conclusion: The total incidence of GC and that of the intestinal-type GC decreased, but the incidence of diffused-type GC increased in 40-49-year-olds. Diffused types of GCs may have a different prognosis compared to intestinal-type GCs in different patient cohorts. Nevertheless, these results should be interpreted with caution in assessing the prognosis in combination with other factors.

The RNA-Binding Protein HuR in Digestive System Tumors

Human antigen R (HuR) is a member of the Hu family of RNA-binding proteins. This molecule, which was first described in tumors nearly two decades ago, has recently received much attention in tumor-related research because it regulates the expression of many tumor-associated molecules through posttranscriptional regulatory mechanisms, thereby affecting biological characteristics. It is suggested that HuR might be a novel therapeutic target and a marker for therapeutic response and prognostic assessment. Increasing evidence supports that HuR also plays critical roles in the development, therapy, and prognosis of digestive system tumors. Herein, we review the relationships between HuR and digestive system tumors, demonstrating the importance of HuR in digestive system tumor diagnosis.

High-Throughput Sequencing of Gastric Cancer Patients: Unravelling Genetic Predispositions Towards an Early-Onset Subtype

Background: Gastric cancer is the fourth most common cause of cancer-related death. Currently, it is broadly accepted that the molecular complexity and heterogeneity of gastric cancer, both inter- and intra-tumor, display important barriers for finding specific biomarkers for the early detection and diagnosis of this malignancy. Early-onset gastric cancer is not as prevalent as conventional gastric carcinoma, but it is a preferable model for studying the genetic background, as young patients are less exposed to environmental factors, which influence cancer development. Aim: The main objective of this study was to reveal age-dependent genotypic characteristics of gastric cancer subtypes, as well as conduct mutation profiling for the most frequent alterations in gastric cancer development, using targeted next-generation sequencing technology. Patients and methods: The study group included 53 patients, consisting of 18 patients with conventional gastric cancer and 35 with an early-onset subtype. The DNA of all index cases was used for next-generation sequencing, employing a panel of 94 genes and 284 single nucleotide polymorphisms (SNPs) (TruSight Cancer Panel, Illumina), which is characteristic for common and rare types of cancer. Results: From among the 53 samples processed for sequencing, we were able to identify seven candidate genes (STK11, RET, FANCM, SLX4, WRN, MEN1, and KIT) and nine variants among them: one splice_acceptor, four synonymous, and four missense variants. These were selected for the age-dependent differentiation of gastric cancer subtypes. We found four variants with C-Score ≥ 10, as 10% of the most deleterious substitutions: rs1800862 (RET), rs10138997 (FANCM), rs2230009 (WRN), and rs2959656 (MEN1). We identified 36 different variants, among 24 different genes, which were the most frequent genetic alterations among study subjects. We found 16 different variants among the genes that were present in 100% of the total cohort: SDHB (rs2746462), ALK (rs1670283), XPC (rs2958057), RECQL4 (rs4925828; rs11342077, rs398010167; rs2721190), DDB2 (rs326212), MEN1 (rs540012), AIP (rs4930199), ATM (rs659243), HNF1A (rs1169305), BRCA2 (rs206075; rs169547), ERCC5 (rs9514066; rs9514067), and FANCI (rs7183618). Conclusions: The technology of next-generation sequencing is a useful tool for studying the development and progression of gastric carcinoma in a high-throughput way. Our study revealed that early-onset gastric cancer has a different mutation frequency profile in certain genes compared to conventional subtype.

Gastric Cancer: Epidemiology, Risk Factors, Classification, Genomic Characteristics and Treatment Strategies

Gastric cancer (GC) is one of the most common malignancies worldwide and it is the fourth leading cause of cancer-related death. GC is a multifactorial disease, where both environmental and genetic factors can have an impact on its occurrence and development. The incidence rate of GC rises progressively with age; the median age at diagnosis is 70 years. However, approximately 10% of gastric carcinomas are detected at the age of 45 or younger. Early-onset gastric cancer is a good model to study genetic alterations related to the carcinogenesis process, as young patients are less exposed to environmental carcinogens. Carcinogenesis is a multistage disease process specified by the progressive development of mutations and epigenetic alterations in the expression of various genes, which are responsible for the occurrence of the disease.

Development and validation of prognostic nomogram for young patients with gastric cancer

Background

This study was to establish nomogram models for prognostic evaluation of early-onset gastric cancer (EOGC) in both overall survival (OS) and cancer-specific survival (CSS).

Methods

EOGC patients from 2004 to 2015 were retrieved from the surveillance, epidemiology and end results (SEER) and further randomly assigned to training and validation sets. Univariate and multivariate cox analysis was used to screen out significant variables for construction of nomogram. Nomogram models were assessed by concordance index (C-index), calibration plot, receiver operating characteristics (ROCs) curve and decision curve analysis (DCA).

Results

A total of 549 EOGC were selected in this process. OS nomogram was constructed based on tumor size and tumor site. CSS nomogram was constructed based on tumor size, SEER stage and tumor site. In training set, C-index for the OS nomogram was 0.688 [95% confidence intervals (95% CI): 0.629-0.747], CSS nomogram 0.785 (95% CI: 0.735-0.835). In the external validation, the C-index for the OS nomogram was 0.633 (95% CI: 0.579-0.687), while for the CSS nomogram 0.733 (95% CI: 0.686-0.780). High quality of calibration plots both in OS and OS nomogram models was noticed. Nomograms displayed a comparable result to tumor-node-metastasis (TNM) stage and SEER stage for EOGC based on DCA.

Conclusions

The nomogram models provided an insightful and applicable tool to evaluate the prognosis of EOGC both in OS and CSS.

Expression of DNA Damage Response Markers in Early-Onset or Familial Gastric Cancers

Background:

Early-onset or familial gastric cancer (GC) is known to have clinicopathologic profiles different from those of sporadic GC. We aimed to compare DNA damage response marker expression between early-onset or familial GC and sporadic GC.

Methods:

GC samples were obtained from patients who underwent gastrectomy for GC at Seoul National University Hospital. Immunohistochemical analyses of various DNA damage response markers, including BRCA1, BRCA2, MRE11, RAD51C, and γH2AX, were performed using 54 early-onset GC, 59 familial GC, and 337 sporadic GC tissue microarray samples. Correlations between marker expression and clinicopathologic features were evaluated by univariate and multivariate analyses, and overall survival was analyzed.

Results:

The rate of γH2AX positivity was significantly higher (p < 0.001) in early-onset or familial GC than in sporadic GC. In contrast, the rates of MRE11 negativity and RAD51C negativity were significantly higher in sporadic GC than in early-onset or familial GC. BRCA1 negativity was associated with decreased overall survival in sporadic GC (p = 0.002), and MRE11 negativity was associated with decreased overall survival in sporadic GC (p = 0.012).

Conclusion:

Our results show significant differences in DNA damage response marker expression between early-onset or familial GC and sporadic GC.

YWHAE silencing induces cell proliferation, invasion and migration through the up-regulation of CDC25B and MYC in gastric cancer cells: new insights about YWHAE role in the tumor development and metastasis process

We previously observed reduced YWHAE (14-3-3ε) protein expression in a small set of gastric cancer samples. YWHAE may act as a negative regulator of the cyclin CDC25B, which is a transcriptional target of MYC oncogene. The understanding of YWHAE role and its targets is important for the better knowledge of gastric carcinogenesis. Thus, we aimed to evaluate the relationship among YWHAE, CDC25B, and MYC in vitro and in vivo. For this, we analyzed the YWHAE, CDC25B, and MYC expression in YWHA-silenced, CDC25B-silenced, and MYC-silenced gastric cancer cell lines, as well as in gastric cancer and non-neoplastic gastric samples. In gastric cancer cell lines, YWHAE was able to inhibit the cell proliferation, invasion and migration through the reduction of MYC and CDC25B expression. Conversely, MYC induced the cell proliferation, invasion and migration through the induction of CDC25B and the reduction of YWHAE. Most of the tumors presented reduced YWHAE and increased CDC25B expression, which seems to be important for tumor development. Increased MYC expression was a common finding in gastric cancer and has a role in poor prognosis. In the tumor initiation, the opposite role of YWHAE and CDC25B in gastric carcinogenesis seems to be independent of MYC expression. However, the inversely correlation between YWHAE and MYC expression seems to be important for gastric cancer cells invasion and migration. The interaction between YWHAE and MYC and the activation of the pathways related to this interaction play a role in the metastasis process.

Gastric cancer: epidemiology, prevention, classification, and treatment

Gastric cancer is the second most common cause of cancer-related deaths in the world, the epidemiology of which has changed within last decades. A trend of steady decline in gastric cancer incidence rates is the effect of the increased standards of hygiene, conscious nutrition, and Helicobacter pylori eradication, which together constitute primary prevention. Avoidance of gastric cancer remains a priority. However, patients with higher risk should be screened for early detection and chemoprevention. Surgical resection enhanced by standardized lymphadenectomy remains the gold standard in gastric cancer therapy. This review briefly summarizes the most important aspects of gastric cancers, which include epidemiology, risk factors, classification, diagnosis, prevention, and treatment. The paper is mostly addressed to physicians who are interested in updating the state of art concerning gastric carcinoma from easily accessible and credible source.

Clinicopathological Significance of Overexpression of TSPAN1, KI67 and CD34 in Gastric Carcinoma

To investigate the expression of TSPAN1 (Gene ID: 10103), Ki67 and CD34 in gastric carcinomas and the clinicopathological significance, the expression of TSPAN1, Ki67 and CD34 was detected in 86 cases of gastric carcinoma, paraffin-embedded sections using an immunohistochemical method. The rates of overexpression of TSPAN1, Ki67 and CD34 in gastric carcinomas were 56.98%, 74.42%, and 62.79%, respectively. The overexpression of these markers was positively correlated with clinical stage and negatively correlated with survival rates (at 3 and 5 years). The overexpression of TSPAN1 and Ki67 was negatively correlated with carcinoma differentiation, and the overexpression of TSPAN1 and CD34 was positively correlated with infiltration and lymph node status of the tumor. Thus, overexpression of TSPAN1, Ki67 and CD34 in gastric cancer tissues is associated with development of the cancer. The detection of expression of TSPAN1, Ki67 and CD34 in gastric cancer may provide useful prognostic information for patients with the disease.

Genetic variability in LMP2 and LMP7 is associated with the risk of esophageal squamous cell carcinoma in the Kazakh population but is not associated with HPV infection

The Kazakh population in Xinjiang Province in northwestern China exhibits a high incidence of esophageal squamous cell carcinoma (ESCC). Although the etiology of esophageal carcinoma (EC) has not been elucidated, there are reports of the involvement of an immunologic mechanism. In the current study, 268 Kazakh ESCC patients and 500 age- and sex-matched control subjects were recruited. DNA was extracted from paraffin-embedded tumor specimens from the patients and peripheral blood lymphocytes from the controls and used for LMP2/LMP7 genotyping. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect LMP2/LMP7 gene single-nucleotide polymorphisms (SNPs). We found a clear increased risk of ESCC in the Kazakh population for the heterozygous LMP2 R/C genotype and the homozygous C/C genotype (OR = 1.470, 95%CI = 1.076–2.008, p = 0.015 forLMP2R/C; OR = 2.048, 95% CI = 1.168–3.591, p = 0.011 for LMP2 C/C). Conversely, the heterozygous LMP7 Q/K polymorphism was found to decrease the risk of ESCC in this population (OR = 0.421, 95% CI = 0.286–0.621, p = 8.83×10⁻⁶). Moreover, LMP2 R/C+C/C genotype was associated with increased tumor invasion depth (p = 0.041). Haplotype analysis showed that haplotype A, which includes wild-type homozygous LMP2/TAP1 and mutant LMP7, decreases susceptibility to ESCC in the Kazakh population; in contrast, haplotype E, which includes wild-type homozygous LMP2/LMP7/TAP1, acts as a risk factor for increased susceptibility to ESCC. This is the first study to report that the heterozygous LMP2 R/C and homozygous C/C genotypes increase susceptibility to ESCC in the Kazakh population and that the heterozygous LMP7 Q/K genotype decreases susceptibility to ESCC in this population. Nevertheless, neither LMP2 nor LMP7 was associated with human papillomavirus (HPV) infection. Understanding LMP2/LMP7 genetic variability will provide a new therapeutic perspective for Kazakh patients with ESCC.

Prognosis of Pregnancy-Associated Gastric Cancer: An Age-, Sex-, and Stage-Matched Case-Control Study

Background/Aims

Pregnancy-associated gastric cancer is a rare condition. This case-control study was performed to identify the clinicopathological features and prognostic factors of pregnancy-associated gastric cancer.

Methods

All consecutive patients who presented to our tertiary referral hospital with pregnancy-associated gastric cancer from 1991 to 2012 were identified. Two age-, sex-, and stage-matched controls for each case were also identified from the records. Clinicopathological, gynecological, and oncological outcomes were recorded. Immunohistochemical staining was performed for estrogen receptor, progesterone receptor, epidermal growth factor receptor, human epidermal growth factor receptor, and E-cadherin. Fluorescence in situ hybridization was performed for fibroblast growth factor receptor 2.

Results

The median overall survival rates of the pregnancy-associated gastric cancer and control groups were 7.0 months and 15.0 months, respectively (p=0.189). Poor prognostic factors included advanced stage and tumor location in the corpus or the entire stomach but not pregnancy status or loss of E-cadherin. Pregnancy-associated gastric cancer was associated with a longer time from diagnosis to treatment (21 days vs 7 days, p=0.021). The two groups did not differ in the expression of the receptors or E-cadherin.

Conclusions

The dismal prognosis of pregnancy-associated gastric cancer may related to the tumor stage and location rather than to pregnancy itself.

Cytoplasmic overexpression of RNA-binding protein HuR is a marker of poor prognosis in meningioma, and HuR knockdown decreases meningioma cell growth and resistance to hypoxia

HuR regulates cytoplasmic mRNA stability and translatability, and the HuR expression level has been shown to correlate with poor disease outcome in several cancer types; however, the prognostic value and potential pro-oncogenic properties of HuR in meningioma remain unclear. Thus, in the present study, we analysed 85 meningioma tissue samples to establish the relationship between HuR expression, tumour cell proliferation, and/or patient survival. In addition, we examined the anti-proliferative effects of HuR knockdown in two meningioma cell lines (IOMM-Lee and Ben-Men-1) and conducted transcriptome-wide analyses (IOMM-Lee cells) to elucidate the molecular consequences of HuR knockdown. The results of the present study showed HuR cytoplasmic expression to correlate positively with tumour grade (p = 1.2 × 10^-8 ) and negatively with progression-free and overall survival (p = 0.01) time in human meningioma tissues. In vitro, siHuR-induced HuR knockdown was shown to reduce the growth of both Ben-Men-1 (p = 2 × 10^-8 ) and IOMM-Lee (p = 4 × 10^-9 ) cells. Transcriptome analyses revealed HuR knockdown in IOMM-Lee cells to deregulate the HIF1A signalling pathway (p = 1.5 × 10^-6 ) and to up-regulate the expression of genes essential for the assembly of the cytoplasmic mRNA processing body, global genome nucleotide-excision repair, poly(A)-specific ribonuclease activity, the positive regulation of apoptosis and of cell cycle arrest, and the negative regulation of RNA splicing [p(FDR) < 0.001]. Interestingly, HuR knockdown under hypoxic culture conditions further potentiated the effects of HuR knockdown on cell growth, apoptosis, and HIF1A expression. We thus conclude that cytoplasmic HuR expression is a marker of poor prognosis in meningioma and that HuR is a promising potential therapeutic target for use in tumours refractory to standard therapies. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Molecular mechanisms of long noncoding RNAs on gastric cancer

Long noncoding RNAs (lncRNAs) are non-protein coding transcripts longer than 200 nucleotides. Aberrant expression of lncRNAs has been found associated with gastric cancer, one of the most malignant tumors. By complementary base pairing with mRNAs or forming complexes with RNA binding proteins (RBPs), some lncRNAs including GHET1, MALAT1, and TINCR may mediate mRNA stability and splicing. Other lncRNAs, such as BC032469, GAPLINC, and HOTAIR, participate in the competing endogenous RNA (ceRNA) network. Under certain circumstances, ANRIL, GACAT3, H19, MEG3, and TUSC7 exhibit their biological roles by associating with microRNAs (miRNAs). By recruiting histone-modifying complexes, ANRIL, FENDRR, H19, HOTAIR, MALAT1, and PVT1 may inhibit the transcription of target genes in cis or trans. Through these mechanisms, lncRNAs form RNA-dsDNA triplex. CCAT1, GAPLINC, GAS5, H19, MEG3, and TUSC7 play oncogenic or tumor suppressor roles by correlated with tumor suppressor P53 or onco-protein c-Myc, respectively. In conclusion, interaction with DNA, RNA and proteins is involved in lncRNAs' participation in gastric tumorigenesis and development.

Expression profile of E-cadherin, estrogen receptors, and P53 in early-onset gastric cancers

Early-onset gastric cancer (EOGC) is predominant in females, diffuse histology, and hereditary pattern. Germline mutation of CDH1 and p53 has been reported previously and female dominance was speculated to be associated with estrogen and its receptors. Expression of E-cadherin, estrogen receptor α (ERα), estrogen receptor β (ERβ), and p53 in EOGC remains unclear, which was the focus of this study, to assess clinical significance of their expression in EOGC. The expression of E-cadherin, ERα, ERβ, and p53 in tumors and normal tissues from surgically resected EOGCs was assessed by immunohistochemistry (n = 139) and Western blot (n = 7) methods, respectively. The expression in tumor tissues was significantly higher for ERα, ERβ, and p53, but lower for E-cadherin, compared to uninvolved mucosa. Positive staining of ERβ and p53 was more frequently observed in younger patients with advanced TNM stages. For E-cadherin, significant correlation was observed between the immunopositivity and TNM stages IA+IB. P53-negative patients had significantly better outcomes than p53-positive patients. Significant association between expression of E-cadherin and histologic types was found in familial, but not in sporadic, EOGC. In conclusion, our results demonstrated E-cadherin may have a role in initiation of EOGC and positive ERβ and p53 expression may partially explained early-onset and tumor progression of EOGC.

Clinical characteristics of young-age onset gastric cancer in Korea

Background

Gastric cancer is the fourth most common cancer worldwide and more frequently detected in Asian countries including Korea and Japan. The incidence of young-age gastric cancer (GC) is increasing worldwide, but clinical behavior of young-age GC patients is not well established. We retrospectively analyzed the clinical features and outcomes of GC diagnosed at young-age population.

Methods

Between Jan. 2009 to Jan. 2015, 163 patients diagnosed as early, advanced, recurrent, or metastatic GC at ages between 22 ~ 39 years were analyzed. Based on medical records, authors analyzed the clinicopathologic characteristics and survival outcomes including overall survival (OS), disease free survival (DFS), and progression free survival (PFS).

Results

One-hundred and four patients (82.8 %) were diagnosed as GC at their thirties; especially 81 patients (31.2 %) patients were diagnosed over 35 years of age. The ratio of early GC and advanced GC were relatively similar (47.2 % vs. 52.8 %, respectively). Among stage II and III patients, 45 patients received 5-FU based adjuvant chemotherapy and recurrence rate was 48.9 %. Among patients diagnosed as recurrent or metastatic GC, recurrent GC patients showed relatively superior PFS and OS after cancer recurrence, compared to metastatic GC patients, but without statistical significance. Among metastatic GC patients, patients receiving palliative debulking surgery for ovary metastases showed superior PFS compared to patients who only received palliative systemic chemotherapy (P = 0.021, PFS 7.7 vs. 3.37 months, respectively).

Conclusions

Young age GC were commonly diagnosed at their thirties, without sexual predominance. The incidence of advanced GC in young age patients were higher compared to general patient population. Among recurrent GC patients, palliative debulking surgery might have role for superior survival outcomes. Considering relatively higher incidence for advanced GC, active surveillance for gastric cancer is warranted.

Periodic Endoscopies Might Not Increase the Detection of Early Gastric Cancer in a Young Population

Background

Screening endoscopies in individuals 40 years or older in regions where gastric cancer is prevalent increase the diagnosis of gastric cancer at an early stage. However, the benefits of screening endoscopies in a young population (<40 years) have not been evaluated.

Methods

We reviewed data from patients less than 40 years old who underwent endoscopic submucosal dissection or surgery for initial-onset gastric cancer. We also administered a questionnaire to gather information concerning periodic endoscopic inspections and the period from the penultimate endoscopy to diagnosis.

Results

Of the 564 patients in this study, 101 (17.9%) patients underwent screening endoscopy within 24 months of their gastric cancer diagnosis. Lesion size was significantly smaller in the ≤24 months group than in the >24 month group (23.8 mm [standard deviation, 22.2 mm] vs. 30.5 mm [standard deviation, 23.1 mm], P = 0.008). However, the proportion of patients with early gastric cancer did not differ between the two groups (≤24 months vs. >24 months group; 67.6% vs. 65.7%, P = 0.712). On multivariable analysis, periodic endoscopies did not influence the early diagnosis of gastric cancer (with >24 months as the reference group: ≤24 months, odds ratio = 0.939, 95% confidence interval = 0.583–1.513).

Conclusion

Although periodic endoscopies aided in the detection of gastric cancer when lesions were smaller in size, they seemed not to increase the proportion of patients with early gastric cancer in young patients diagnosed with resectable gastric cancer.

Melatonin set out to ER stress signaling thwarts epithelial mesenchymal transition and peritoneal dissemination via calpain-mediated C/EBPβ and NFκB cleavage

Peritoneal dissemination of tumor has high mortality and is associated with the loss of epithelial features, acquisition of motile mesenchymal morphology characteristics, and invasive properties by tumor cells. Melatonin is an endogenously produced molecule in all plant species that is known to exert antitumor activity, but to date, its underlying mechanisms and antiperitoneal metastasis efficacy is not well defined. This study determined the antiperitoneal dissemination potential of melatonin in vivo and assessed its association with the inhibition of epithelial-to-mesenchymal transition (EMT) signaling mechanism by endoplasmic reticulum (ER) stress, which may be a major molecular mechanism of melatonin against cancer. The results demonstrate that melatonin inhibited peritoneal metastasis in vivo and activated ER stress in Cignal ERSE Reporter Assay, organelle structure in transmission electron microscopy images, calpain activity, and protein biomarkers like p-elf2α. Moreover, the overexpression of transcription factor C/EBPβ in gastric cancer interacted with NFκB and further regulates COX-2 expression. These were dissociated and downregulated by melatonin, as proven by immunofluorescence imaging, immunoprecipitation, EMSA, and ChIP assay. Melatonin or gene silencing of C/EBPβ decreased the EMT protein markers (E-cadherin, Snail, and Slug) and Wnt/beta-catenin activity by Topflash activity, and increased ER stress markers. In an animal study, the results of melatonin therapy were consistent with those of in vitro findings and attenuated systemic proangiogenesis factor production. In conclusion, C/EBPβ and NFκB inhibition by melatonin may impede both gastric tumor growth and peritoneal dissemination by inducing ER stress and inhibiting EMT.

Molecular alterations in gastric cancer with special reference to the early-onset subtype

Currently, gastric cancer (GC) is one of the most frequently diagnosed neoplasms, with a global burden of 723000 deaths in 2012. It is the third leading cause of cancer-related death worldwide. There are numerous possible factors that stimulate the pro-carcinogenic activity of important genes. These factors include genetic susceptibility expressed in a single-nucleotide polymorphism, various acquired mutations (chromosomal instability, microsatellite instability, somatic gene mutations, epigenetic alterations) and environmental circumstances (e.g., Helicobcter pylori infection, EBV infection, diet, and smoking). Most of the aforementioned pathways overlap, and authors agree that a clear-cut pathway for GC may not exist. Thus, the categorization of carcinogenic events is complicated. Lately, it has been claimed that research on early-onset gastric carcinoma (EOGC) and hereditary GC may contribute towards unravelling some part of the mystery of the GC molecular pattern because young patients are less exposed to environmental carcinogens and because carcinogenesis in this setting may be more dependent on genetic factors. The comparison of various aspects that differ and coexist in EOGCs and conventional GCs might enable scientists to: distinguish which features in the pathway of gastric carcinogenesis are modifiable, discover specific GC markers and identify a specific target. This review provides a summary of the data published thus far concerning the molecular characteristics of GC and highlights the outstanding features of EOGC.

Association between LMP2 and LMP7 gene polymorphisms and the risk of gastric cancer: A case-control study

The integrality of low molecular weight protein (LMP)2/LMP7 function plays an important role in the processing of GC cell antigens. The purpose of the present hospital-based case-control study was to estimate the effect of polymorphisms in the LMP2 and LMP7 genes on the risk of GC. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to distinguish the Arg to His substitution at codon 60 of LMP2 (LMP2-60) and the Gln to Lys substitution at codon 145 of LMP7 (LMP7-145) in 502 gastric cancer patients and 502 age and gender-matched cancer-free control individuals. The Lys allele of the LMP7-145 variant was more frequent in GC patients compared with control individuals [P=0.004; adjusted odds ratio (OR), 1.39; 95% confidence interval (CI), 1.11-1.74]. The Gln/Lys and Lys/Lys genotypes increased the risk of GC compared with the Gln/Gln genotype (P=0.049 and P=0.041, respectively; adjusted OR, 1.32 and 2.13, respectively; 95% CI, 1.00-1.73 and 1.03-4.39, respectively). Compared with the Gln/Gln genotype, the LMP7-145 Gln/Lys and Lys/Lys variants of the LMP7 gene were also associated with increased susceptibility to GC (P=0.017; adjusted OR, 1.38; 95% CI, 1.06-1.80). Haplotype analysis revealed that the LMP2 (Arg)-LMP7 (Lys) haplotype was associated with increased risk of GC (P=0.013, adjusted OR=1.34, 95% CI=1.06-1.70). Stratified analysis revealed that the association between the risk of GC and the variant genotypes of LMP7-145 was stronger in older individuals (>59 years), males and non-smokers. However, no association between the LMP2-60 polymorphism and the risk of GC was observed. The present results suggest that the LMP7-145 genetic variant contributes to increased susceptibility to GC, and the Lys allele is an independent risk factor for GC.

The role of biological markers of epithelial to mesenchymal transition in oesophageal adenocarcinoma, an immunohistochemical study

BACKGROUND

E-cadherin, β-catenin, epidermal growth factor receptor (EGFR), neuronal cadherin (N-cadherin) and Cyclin D1 are involved in epithelial to mesenchymal transition (EMT). However, the prognostic significance of EMT markers in oesophageal adenocarcinoma (OAC) is unknown. Aim of this study was to evaluate the prognostic value of, and the association between different EMT markers in OAC.

METHODS

Tumour cores of 154 patients with OAC were included in a tissue microarray. Scoring criteria was based on immunohistochemical staining intensity.

RESULTS

EMT-associated markers were expressed in OAC: reduced membranous E-cadherin and β-catenin were seen in 11.4% and 51.7%, nuclear β-catenin in 19.1% and EGFR and Cyclin D1 overexpression in 56.5% and 27.4% of tumours. Mesenchymal marker N-cadherin was not expressed in OAC. A positive correlation was seen between membranous β-catenin and E-cadherin expression (R=0.209, p=0.001) and between EGFR and Cyclin D1 (R=0.257, p=0.002). In univariate analysis, EGFR overexpression and membranous β-catenin staining were significantly associated with a poor survival (HR 2.145; 95% CI 1.429 to 3.218, p<0.001 and HR 1.665; 95% CI 1.114 to 2.488; p=0.013). However, Cyclin D1 (HR 1.092; 95% CI 0.702 to 1.698; p=0.697), nuclear β-catenin (HR 1.322; 95% CI 0.799 to 2.189; p=0.277) and E-cadherin (HR 1.012; 95% CI 0.554 to 1.851; p=0.968) were not associated with survival. In multivariate analysis, EGFR overexpression was an independent prognostic factor for poor survival (HR 1.678; 95% CI 1.055 to 2.668; p=0.029) together with T stage (HR 2.759; 95% CI 1.356 to 5.576; p=0.005).

CONCLUSIONS

This study supports the presence of EMT in OAC. Moreover, EGFR overexpression was independently associated with a poor survival.

Clinical significance of HuR expression in human malignancy

Hu-antigen R (HuR) is an RNA-binding protein that regulates the stability, translation, and nucleus-to-cytoplasm translocation of target mRNAs. The aim of the present review was to summarize and present the currently available information in the English literature on HuR expression in various human tumors, verifying its possible clinical significance. HuR function is directly linked to its subcellular localization. In normal cells, HuR is mostly localized in the nucleus, while in malignant cells, an increase in cytoplasmic HuR levels has been noted, in both cell lines and tissue samples. Moreover, in malignancy, elevated HuR expression levels and cytoplasmic immunohistochemical pattern have been correlated with advanced clinicopathological parameters and altered expression levels of proteins implicated in neoplasia. Additionally, elevated HuR expression levels and mainly cytoplasmic immunohistochemical pattern were correlated with decreased patients' survival rate in various human tumors. HuR is a putative drug target for cancer therapy, since it is expressed ubiquitously in malignant clinical samples and has an apparently consistent role in tumor formation and progression.

Comprehensive analysis of HPV expression in laryngeal squamous cell carcinoma

Role of human papillomavirus (HPV) in laryngeal carcinoma remains controversial. The aim of this study is to evaluate the role of HPV in laryngeal squamous cell carcinoma by determining presence of markers of viral infection. HPV DNA and E6*I mRNA status was determined by type-specific E7 PCR bead-based multiplex genotyping and RT-PCR assays in laryngeal squamous cell carcinoma biopsy samples. p16(INK4a) and COX-2 expression was determined by immunohistochemistry. Four cases out of 32 (13%) were HPV DNA+: HPV 11 (n = 1), HPV 31 (n = 3), HPV 59 (n = 1). One double infection: HPV 11 and HPV 31. p16(INK4a) was overexpressed in three cases (9%) and COX-2 in 17 cases (53%). Two of four HPV DNA+ samples had E6*I mRNA for HPV 31 and overexpressed p16(INK4a) and COX-2. HPV appears to play an active role in a small subset of laryngeal squamous cell carcinoma. p16(INK4a) can be used as a surrogate marker of transcriptionally active HPV infection; COX-2 expression had no correlation with HPV DNA and/or RNA positivity.

Prognostic value of epidermal growth factor receptors in gastric cancer: a survival analysis by Weibull model incorporating long-term survivors

BACKGROUND

There is no consensus about the prognostic role of HER2 expression and that of other members of the EGFR family in gastric cancer patients. The aim of this study was to evaluate the prognostic value of the EGFR family in gastric cancer.

METHODS

This retrospective study included 201 patients with gastric and esophagogastric junction adenocarcinoma stages 0-IV (AJCC 6th edition) who underwent primary tumor resection. Tissues from primary tumors were analyzed by tissue microarray technology and immunohistochemistry. Correlations between receptor expression and clinicopathological characteristics were performed according to the chi-square test. Survival analysis was calculated according to the Weibull model with a mixture model incorporating long-term survivors. Multivariate analysis of prognostic factors was performed by a regression model incorporating long-term survivors with the Weibull distribution.

RESULTS

Membrane expression of HER1, HER2, and HER4 were 9, 17, and 15 %, respectively. No membrane expression of HER3 was observed. Cytoplasmic expression of HER1, HER3, and HER4 were 45, 62, and 24 %, respectively. HER2 and HER3 expression were correlated (p < 0.001) and associated with intestinal-type histology (p = 0.001 and p < 0.001, respectively) and advanced age (p = 0.011 and p = 0.008, respectively). According to a regression model adjusted for age, surgical radicality, surgical modality, Laurén histology, adjuvant therapy, TNM stage, and receptor expressions, only TNM stage showed prognostic influence.

CONCLUSIONS

According to analysis by a parametric model, the EGFR family did not have prognostic influence in the gastric cancer population studied. The data presented showed a correlation between HER2 and HER3 expression, which might suggest a potential role for HER2-HER3 heterodimerization inhibitors.

Personalizing therapies for gastric cancer: molecular mechanisms and novel targeted therapies

Globally, gastric cancer is the 4(th) most frequently diagnosed cancer and the 2(nd) leading cause of death from cancer, with an estimated 990000 new cases and 738000 deaths registered in 2008. In the advanced setting, standard chemotherapies protocols acquired an important role since last decades in prolong survival. Moreover, recent advances in molecular therapies provided a new interesting weapon to treat advanced gastric cancer through anti-human epidermal growth factor receptor 2 (HER2) therapies. Trastuzumab, an anti-HER2 monoclonal antibody, was the first target drug in the metastatic setting that showed benefit in overall survival when in association with platinum-5-fluorouracil based chemotherapy. Further, HER2 overexpression analysis acquired a main role in predict response for trastuzumab in this field. Thus, we conducted a review that will discuss the main points concerning trastuzumab and HER2 in gastric cancer, providing a comprehensive overview of molecular mechanisms and novel trials involved.

Multiple functions of the RNA-binding protein HuR in cancer progression, treatment responses and prognosis

The human embryonic lethal abnormal vision-like protein, HuR, is a member of the Hu family of RNA-binding proteins. Over the past decade, this ubiquitously expressed protein has been extensively investigated in cancer research because it is involved in the regulation of mRNA stability and translation in many cell types. HuR activity and function is associated with its subcellular distribution, transcriptional regulation, translational and post-translational modifications. HuR regulation of target mRNAs is based on the interaction between the three specific domains of HuR protein and one or several U- or AU-rich elements (AREs) in the untranslated region of target mRNAs. A number of cancer-related transcripts containing AREs, including mRNAs for proto-oncogenes, cytokines, growth factors, and invasion factors, have been characterized as HuR targets. It has been proposed that HuR has a central tumorigenic activity by enabling multiple cancer phenotypes. In this review, we comprehensively survey the existing evidence with regard to the diverse functions of HuR in caner development and progression. The current data also suggest that HuR might be a novel and promising therapeutic target and a marker for treatment response and prognostic evaluation.

Loss of trefoil factor 1 is regulated by DNA methylation and is an independent predictive factor for poor survival in advanced gastric cancer

Trefoil factor 1 (TFF1) is considered to be a tumor suppressor gene in gastric cancer. However, the role of TFF1 expression and its regulation in gastric cancer patients remain unclear. The aims of this study were to clarify the clinical significance of TFF1 and to determine its regulatory mechanisms. We assessed the immunohistochemical expression of TFF1 in 182 gastric cancer patients and examined whether or not TFF1 is associated with the clinicopathological factors and patient survival. In vitro study using TFF1 knockdown gastric cancer cells evaluated the role of TFF1 in cancer invasion. Bisulfite sequencing was performed to assess DNA methylation of TFF1 in cells and resected tissues. Patients with low expression of TFF1 showed a significantly deeper invasion of the tumor than those with high expression (p=0.037). Low expression of TFF1 was also associated with a poor survival (p=0.029) in 108 patients who were treated by surgery alone. Both TFF1 expression and lymph node metastasis are independent predictive factors for disease-specific survival in a multivariate analysis. In an in vitro study, invasive power of the cells was significantly increased in the TFF1‑deficient cells compared with the control cells. Bisulfate sequencing showed that TFF1 expression is strongly dependent on DNA methylation in both gastric cancer cells and tissues. Interestingly, methylation status of two specific CpG sites, which are located close to a TATA box and hypoxia response element (HRE), determined the TFF1 expression in the resected tissues. TFF1 expression is silenced by DNA methylation and is associated with tumor invasion and a poor survival in gastric cancer patients. The expression and̸or methylation status of TFF1 may, therefore, serve as a useful biomarker for predicting survival in patients with advanced gastric cancer.

Clinical implication of 14-3-3 epsilon expression in gastric cancer

AIM: To evaluate for the first time the protein and mRNA expression of 14-3-3ε in gastric carcinogenesis.

METHODS: 14-3-3ε protein expression was determined by western blotting, and mRNA expression was examined by real-time quantitative RT-PCR in gastric tumors and their matched non-neoplastic gastric tissue samples.

RESULTS: Authors observed a significant reduction of 14-3-3ε protein expression in gastric cancer (GC) samples compared to their matched non-neoplastic tissue. Reduced levels of 14-3-3ε were also associated with diffuse-type GC and early-onset of this pathology. Our data suggest that reduced 14-3-3ε may have a role in gastric carcinogenesis process.

CONCLUSION: Our results reveal that the reduced 14-3-3ε expression in GC and investigation of 14-3-3ε interaction partners may help to elucidate the carcinogenesis process.

Increased trefoil factor 3 levels in the serum of patients with three major histological subtypes of lung cancer

Lung cancer is the most common cause of cancer-related deaths in the world. The trefoil factor (TFF) family is composed of three thermostable, and protease-resistant proteins, named TFF1, TFF2 and TFF3. TFF protein levels have been found to be related to the development of various types of cancer. However, it is still unclear whether TFF proteins are differentially expressed in the serum of different histological subtypes of lung cancer compared to healthy individuals. In this study, we investigated the levels of TFF proteins in serum and lung tissues of 130 lung cancer patients (58 squamous cell lung carcinoma cases, 43 adenocarcinoma cases and 29 SCLC cases) and 60 healthy individuals. It was found that TFF1 and TFF2 have similar or slightly higher levels in these three subtypes of lung cancer compared to healthy individuals, while TFF3 levels were significantly higher in the examined lung cancer cases compared to healthy individuals. Immunoblot analyses of TFF1, TFF2 and TFF3 indicated that lung cancer tissues and lung cancer cell lines have a higher expression of the TFF3 protein, but not of TFF1 or TFF2 proteins, compared to tissues from healthy individuals or from the normal cell line. Quantitative RT-PCR analysis indicated higher levels of TFF3, but not TFF1 and TFF2, transcripts in lung cancer tissues or cell lines. These results show increased TFF3 levels in serum and lung tissues, suggesting that TFF3 may serve as a promising, easily detected biomarker of lung cancer.

Inhibition of cyclooxygenase-2 causes regression of gastric adenomas in trefoil factor 1 deficient mice

Cyclooxygenase-2 (Cox-2) expression is a marker of reduced survival in gastric cancer patients, and inhibition of Cox-2 suppresses gastrointestinal carcinogenesis in experimental animal models. To investigate the role of Cox-2 in gastric carcinogenesis in vivo, we utilized trefoil factor 1 (Tff1) deficient mice, which model the neoplastic process of the stomach by developing gastric adenomas with full penetrance. These tumors express Cox-2 protein and mRNA, and we have now investigated the effects of genetic deletion of the mouse Cox-2 gene [also known as prostaglandin-endoperoxide synthase 2 (Ptgs2)] and a Cox-2 selective drug celecoxib. Our results show that genetic deletion of Cox-2 in the Tff1 deleted background resulted in reduced adenoma size and ulceration with a chronic inflammatory reaction at the site of the adenoma. To characterize the effect of Cox-2 inhibition in more detail, mice that had already developed an adenoma were fed with celecoxib for 8-14 weeks, which resulted in disruption of the adenoma that ranged from superficial erosion to deep ulcerated destruction accompanied with chronic inflammation. Importantly, mice fed with celecoxib for 16 weeks, followed by control food for 9 weeks, redeveloped a complete adenoma with no detectable inflammatory process. Finally, we determined the identity of the Cox-2 expressing cells and found them to be fibroblasts. Our results show that inhibition of Cox-2 is sufficient to reversibly disrupt gastric adenomas in mice.

Prognostic significance of cyclooxygenase-2, epidermal growth factor receptor 1, and microvascular density in gastric cancer

Gastric cancer remains a significant global health burden with poor treatment outcome. New treatment modalities that target inflammation, proliferation, and angiogenesis have been used in various cancers, including gastric cancer. We sought to study the pattern of expression of two important proteins, cyclooxygenase-2 and epidermal growth factor receptor, and their association with microvascular density, clinicopathological features, and survival in Arab Omani patients with gastric cancer. Formalin-fixed, paraffin-embedded tumors were studied by immunohistochemistry using monoclonal antibodies to cyclooxygenase-2, epidermal growth factor receptor, and CD34. The immunohistochemical results were correlated with clinicopathological features and survival. In our study population, we found a male/female ratio of 72:43, a median age of 59 years, stage III and IV incidence of 66.9%, and a median follow-up of 96 months. Positive expression rates of cyclooxygenase-2 and epidermal growth factor receptor were 89.6 and 23.5%, respectively. The median microvascular density value was 52.5. When this value was determined as the cut-off point, 50% of patients were found to have high microvascular density. Epidermal growth factor receptor over-expression correlated with high microvascular density values, advanced lymph node involvement (N3), and TNM stage presentation (III and IV). Similarly, lymph node involvement was associated with cyclooxygenase-2 over-expression and high microvascular density. Univariate analysis showed that epidermal growth factor receptor over-expression, pathological T3 and T4 disease, and overall stage III and IV disease were adverse prognostic factors. On multivariate analysis using a Cox regression model, expression of epidermal growth factor receptor, and advanced TNM stage were significant adverse prognostic factors for overall survival. Expression of epidermal growth factor receptor in Arab Omani patients with gastric cancer correlates with aggressive tumor characteristics and is an independent prognostic factor. Further clinical studies are needed to evaluate the utility of epidermal growth factor receptor immunohistochemistry as a tool for gastric cancer treatment.

Association between ITGA2 C807T polymorphism and gastric cancer risk

AIM: To evaluate the impact of the ITGA2 gene polymorphism on gastric cancer risk.

METHODS: A hospital-based case-control study was conducted, including 307 gastric cancer patients and 307 age- and gender-matched control subjects. The genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS: The frequencies of the wild and variant genotypes in cases were significantly different from those of controls (P = 0.019). Compared with individuals with the wild genotype CC, subjects with the variant genotypes (CT + TT) had a significantly higher risk of gastric cancer (adjusted odds ratio = 1.57, 95% CI = 1.13-2.17, P = 0.007). In stratified analyses, the elevated gastric cancer risk was especially evident in older individuals aged > 58 years, nonsmokers and rural subjects. Further analyses revealed that the variant genotypes were associated with poor tumor differentiation and adjacent organ invasion in the sub-analysis of gastric cancer patients.

CONCLUSION: The ITGA2 gene C807T polymorphism may be associated with an increased risk of gastric cancer, differentiation and invasion of gastric cancer.