Significance In Gastric Adenocarcinoma Research Articles

CD44v3 is a marker of invasive cancer stem cells driving metastasis in gastric carcinoma

BackgroundCancer stem cells (CSCs) are at the origin of tumour initiation and progression in gastric adenocarcinoma (GC). However, markers of metastasis-initiating cells remain unidentified in GC. In this study, we characterized CD44 variants expressed in GC and evaluated the tumorigenic and metastatic properties of CD44v3+ cells and their clinical significance in GC patients.MethodsUsing GC cell lines and patient-derived xenografts, we evaluated CD44+ and CD44v3+ GC cells molecular signature and their tumorigenic, chemoresistance, invasive and metastatic properties, and expression in patients-derived tissues.ResultsCD44v3+ cells, which represented a subpopulation of CD44+ cells, were detected in advanced preneoplastic lesions and presented CSCs chemoresistance and tumorigenic properties in vitro and in vivo. Molecular and functional analyses revealed two subpopulations of gastric CSCs: CD44v3+ CSCs with an epithelial-mesenchymal transition (EMT)-like signature, and CD44+/v3– CSCs with an epithelial-like signature; both were tumorigenic but CD44v3+ cells showed higher invasive and metastatic properties in vivo. CD44v3+ cells detected in the primary tumours of GC patients were associated with a worse prognosis.ConclusionCD44v3 is a marker of a subpopulation of CSCs with metastatic properties in GC. The identification of metastasis-initiating cells in GC represents a major advance for further development of anti-metastatic therapeutic strategies.

The immune checkpoint CD73 (NT5E) in gastric adenocarcinoma (GAC): Biological characterization and clinical implications.

235 Background: CD73, an ecto-5’-nucleotidase (NT5E), serves as an immune checkpoint by generating adenosine, which in turn leads to immune-suppression and immune-escape. Elevated tissue levels of CD73 have been linked to poor patient survival across several cancer types and CD73 blockade is currently being tested in clinical trials. The biological role of CD73 and its translational relevance is largely unexplored in gastric adenocarcinoma (GAC). Methods: Data mining from transcriptomics big data sources including GEPIA2, HPA and Coexpedia platforms was performed to extract relevant information regarding CD73 expression profile, co-expressed network, association with clinico-pathologic features and survival of GAC. Difference between groups were evaluated by Student's t-test, while correlation analysis was performed through Pearson’s coefficient. Kaplan-Meier methods was used to estimate survival and log-rank test to make comparison between curves. Results: RNA sequencing expression data of 9,736 tumors and 8,587 normal tissue samples from the TCGA and the GTEx projects were analyzed. CD73 mRNA was significantly more expressed in tumour (n = 408) compared to paired normal samples (n = 211) (16.19 vs 3.5 transcripts/million; p < 0.001) and its expression level increased with pathologic stage (from stage I to III). CD73 gene was listed among the top-ten survival-associated genes (p = 4.74e-5) in GAC and together with FGF1 it displayed the greatest survival contribution in this disease among clinically validated genes. Regarding its impact on survival, GAC patients with high CD73 expression (n = 192) experienced a poorer overall survival (OS) compared to the low CD73 group (n = 192) (HR 1.9; log-rank p < 0.001), while regarding relapse-free survival (RFS), the unfavourable value of CD73 expression emerged after 20 months (HR 1.3; log-rank p = 0.23). The prognostic role on OS was validated in a cohort of 354 GAC, where high CD73 expression resulted in 5-year OS of 19% vs 46% (p = 0.00010). When inquiring for context-associated co-expression networks, Caveolin 1 (score = 10.939), FOS-like antigen 1 (score = 7.525) and plasminogen activator urokinase receptor (score = 7.422) were top-ranked co-expressed genes. Conclusions: In this hypothesis-generating analysis, we provided insights into CD73 expression pattern, co-expression networking and prognostic significance in GAC. Future studies in clinically annotated populations are warranted to confirm the value of CD73 in GAC.

Gli1 regulates stemness characteristics in gastric adenocarcinoma

BackgroundGlioma-associated oncogene homolog 1 (Gli1), affects the progression and the stemness characteristics of malignant carcinoma. The aim of the present study was to identify the relation between Glioma-associated oncogene homolog 1 (Gli1) and stemness and determine its clinical significance in gastric adenocarcinoma (GA). We investigated Gli1 expression and its correlation with other stemness-associated proteins in 169 GA samples and 5 GA cell lines.MethodsTo elucidate the role of Gli1 in the clinicopathological significance and stemness of GA, tissues samples from 169 GA patients were collected for immunohistochemistry (IHC). Additionally, MKN74, MKN28, NCI-N87, SNU638, AGS cells were collected for western blotting, MKN28 cells were collected for spheroid formation assay.ResultsResults showed that Gli1 expression was closely related to tumor grade, primary tumor (pT) stage, distant metastasis, clinical stage, gross type, microvessel density, and shorter overall survival (OS). Cox regression analysis verified that Gli1 was an independent prognostic factor for OS. Furthermore, Gli1 expression correlated with the expression of stemness-related genes, CD44, LSD1, and Sox9. Gli1 inhibitor GANT61 significantly decreased the expression of CD44 and LSD1, and spheroid formation ability of the MKN28 cells.ConclusionsIn conclusion, Gli1 may be a poor prognostic indicator and a potential cancer stemness-related protein in GA.

LETM1 is a potential biomarker that predicts poor prognosis in gastric adenocarcinoma

Leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) is closely linked to the occurrence and development of many malignant tumors. Many studies have reported that enhanced expression of LETM1 in several types of human cancers was associated with poor clinical outcomes; however, its clinical significance in gastric adenocarcinoma (GA) has not been elucidated. In this study, we assessed the expression of LETM1 along with the genes related to cancer stemness, cell cycle, and PI3K/Akt signaling in 189 paraffin-embedded GA tissue samples and GA-derived cell lines using immunohistochemistry (IHC), western blotting, and immunofluorescence. Our results showed that the expression of LETM1 was strongly correlated with the tumor grade, primary tumor (pT) stage, lymph node metastasis, clinical stage, and tumor gross type of GA. The Kaplan-Meier survival analysis revealed that patients with GA with high expression of LETM1 exhibit a shorter overall survival (OS) rate. Univariate and multivariate Cox regression analysis indicated that LETM1 is an independent poor prognostic factor of GA. Significantly, LETM1 expression was positively correlated with the expression of cancer stemness-related genes such as CD44 and LGR5 and expression of cell-cycle related gene, cyclin D1. Further, the expression of proteins involved in PI3K/Akt signaling pathway, such as pPI3K-p85 and pAkt-Thr308, was also increased. Additionally, small interfering RNA (esiRNA)-mediated silencing of LETM1 expression in GA-derived cell lines MKN28 and MKN74 strongly inhibited the expression of stemness and cell cycle-related proteins, suppressed cancer cell spheroid formation, migration and invasion ability, and affected cell cycle distribution. Furthermore, the GA-derived cell line AGS exhibited enhanced expression of LETM1, CD44, LGR5, and HIF1-α under hypoxic conditions. Lastly, we blocked PI3K expression using an inhibitor LY294002, which downregulated the expression of LETM1, pPI3K-p85, and pAkt-Thr308. Taken together, our results demonstrate that LETM1 regulates cell proliferation and promotes tumorigenicity of GA, and its overexpression is associated with the poor progression of GA. Therefore, LETM1 could serve as a potential prognostic biomarker and a therapeutic target for the better clinical management of GA.

TNFAIP8 overexpression is associated with lymph node metastasis and poor prognosis in intestinal‐type gastric adenocarcinoma

Tumour necrosis factor alpha-induced protein 8 (TNFAIP8) is implicated in the progression of several human malignancies, but its role in gastric adenocarcinoma is unknown. TNFAIP8 expression and its correlation with clinical significance in gastric adenocarcinoma are evaluated in this study. The expression of TNFAIP8 was determined in primary gastric adenocarcinoma tissues using immunohistochemistry (IHC) and Western blotting analysis. TNFAIP8 expression was higher in gastric adenocarcinoma tissues. Elevated expression of TNFAIP8 in gastric adenocarcinoma was associated significantly with depth of invasion (P=0.024), lymph node metastasis (P=0.038) and Lauren classification (P=0.048). Patients with tumours showing high TNFAIP8 expression had a significantly poorer overall survival (OS) and disease-free survival (DFS) than those with low TNFAIP8 expression in intestinal-type gastric adenocarcinoma (IGA) (P=0.001 for both). In the multivariate Cox analysis, TNFAIP8 expression was an independent prognostic marker for OS and DFS in IGA with P-values of 0.006 and 0.007, respectively. Our data suggest that TNFAIP8 overexpression may contribute to lymph node metastasis and poor prognosis in IGA.

Increased expression of stomatin-like protein 2 (STOML2) predicts decreased survival in gastric adenocarcinoma: a retrospective study

Stomatin-like protein 2 (STOML2), a member of the stomatin, has been reported to be upregulated in several human cancers. However, its role and clinical significance in gastric adenocarcinoma remains unclear to date. The purpose of this retrospective study was to explore whether there was a correlation between the expression of STOML2 by immunohistochemistry and the clinical outcome of a large group of patients with gastric adenocarcinoma. In this retrospective study, we performed immunohistochemistry to evaluation of STOML2 expression in a large panel of gastric adenocarcinoma samples. The receiver operating characteristic method was used to define the STOML2 immunoreactivity score cutoff value. The clinical/prognostic significance of STOML2 expression was analyzed statistically. Kaplan-Meier analysis was used to compare the postoperative survival between groups. STOML2 was overexpressed in gastric cancer compared with paracancerous normal mucosa. Increased STOML2 expression was associated with higher histologic grade (P = 0.047), T category (P < 0.001), and N category (P = 0.01). Patients with high expression of STOML2 demonstrated shortened overall survival compared with those with low expression of STOML2 (median of 38.9 vs. 64.0 months, P < 0.001). Furthermore, STOML2 expression could stratify patients survival in stage N0 (P < 0.001). Multivariate analysis showed that the level of STOML2 expression was an independent prognostic factor in gastric adenocarcinoma (RR = 1.920, P = 0.001). Increased expression of STOML2 suggests unfavorable prognosis for gastric adenocarcinoma patients. Further studies are warranted.

EJ.2 - Therapeutic Potential of Angiogenesis Inhibitors for Gastric Cancer

Gastric adenocarcinoma (GC) is the fourth most common cancer worldwide (7.8% of cancers in 2008) but the second leading cause of cancer death (9.7% of cancer deaths). The highest mortality remains in Korea and Japan (31/100,000 and 23/100,000 respectively). However multiagent chemotherapy improves overall survival and quality of life (QoL) compared with best supportive care (BSC) alone.Attempts to improve these outcomes for treatment in AOGC have focused on targeting growth factor signalling pathways (such as the HER family, mTOR and tumour angiogenesis). In the first line setting, a phase III randomised trial of trastuzumab in HER2-positive AOGC/GOJ (ToGA trial) recently demonstrated a significantly improved median OS in combination with chemotherapy. By contrast blockade of HER- 1 has surprisingly not shown a benefit in combination with chemotherapy. A recent phase III study of everolimus, an inhibitor of the PI3K/Akt/mTOR pathway, also failed to demonstrate a significant improvement OS compared with placebo.As in most other cancers, VEGF and angiogenesis expression or pathway upregulation is of poor prognostic significance in GC. A randomised phase III trial of bevacizumab (anti-VEGF monoclonal antibody) in combination with chemotherapy (CX) in AOGC (AVAGAST) recently demonstrated significant improvement in the secondary efficacy endpoints of PFS (6.7 months vs. 5.3 months; HR = 0.80; p = 0.0037) and ORR (46% vs. 37%; p = 0.0315) with bevacizumab, but did not meet the primary endpoint of OS. Recently a randomised trial of Ramicurumab, a monoclonal antibody VEGFR2 inhibitor, showed a survival benefit compared to best supportive care, in second line therapy. The addition of ramucirumab significantly prolonged median overall survival—the primary endpoint—from 3.8 to 5.2 months (p = 0.0473), comparable to the survival benefit achieved by adding second-line cytotoxic chemotherapy to best supportive care. These two large clinical studies, together with some activity in Phase II studies of sunitinib and sorafenib, combined with a strong biological rationale, provide an impetus to continue exploring the role of antiangiogenic agents in the treatment of gastric cancer. Gastric adenocarcinoma (GC) is the fourth most common cancer worldwide (7.8% of cancers in 2008) but the second leading cause of cancer death (9.7% of cancer deaths). The highest mortality remains in Korea and Japan (31/100,000 and 23/100,000 respectively). However multiagent chemotherapy improves overall survival and quality of life (QoL) compared with best supportive care (BSC) alone. Attempts to improve these outcomes for treatment in AOGC have focused on targeting growth factor signalling pathways (such as the HER family, mTOR and tumour angiogenesis). In the first line setting, a phase III randomised trial of trastuzumab in HER2-positive AOGC/GOJ (ToGA trial) recently demonstrated a significantly improved median OS in combination with chemotherapy. By contrast blockade of HER- 1 has surprisingly not shown a benefit in combination with chemotherapy. A recent phase III study of everolimus, an inhibitor of the PI3K/Akt/mTOR pathway, also failed to demonstrate a significant improvement OS compared with placebo. As in most other cancers, VEGF and angiogenesis expression or pathway upregulation is of poor prognostic significance in GC. A randomised phase III trial of bevacizumab (anti-VEGF monoclonal antibody) in combination with chemotherapy (CX) in AOGC (AVAGAST) recently demonstrated significant improvement in the secondary efficacy endpoints of PFS (6.7 months vs. 5.3 months; HR = 0.80; p = 0.0037) and ORR (46% vs. 37%; p = 0.0315) with bevacizumab, but did not meet the primary endpoint of OS. Recently a randomised trial of Ramicurumab, a monoclonal antibody VEGFR2 inhibitor, showed a survival benefit compared to best supportive care, in second line therapy. The addition of ramucirumab significantly prolonged median overall survival—the primary endpoint—from 3.8 to 5.2 months (p = 0.0473), comparable to the survival benefit achieved by adding second-line cytotoxic chemotherapy to best supportive care. These two large clinical studies, together with some activity in Phase II studies of sunitinib and sorafenib, combined with a strong biological rationale, provide an impetus to continue exploring the role of antiangiogenic agents in the treatment of gastric cancer.

Clinical–pathological implication of human leukocyte antigen-F–positive gastric adenocarcinoma

BackgroundHuman leukocyte antigen (HLA)-F is a nonclassical HLA class I molecule that shows aberrant expression in cancer cells. Although the clinical implications of HLA-F expression in cancer patients have been described, the specific significance of this antigen in gastrointestinal cancer remains unclear. The present study examined the expression pattern and clinical implications of HLA-F in gastric adenocarcinoma. Patients and methodsHLA-F expression was assessed in 179 patients by immunohistochemistry, and its association with clinical parameters including patient survival was analyzed. ResultsHLA-F expression was positive in 30.7% (55/179) of patients and in 50.0% (90/179) of peritumoral infiltrating lymphocytes. HLA-F expression in gastric adenocarcinoma was significantly correlated with the depth of invasion, nodal involvement, and lymphatic and venous invasions (P < 0.01, all). HLA-F positivity of infiltrating cells near the tumor showed no correlation with clinicopathological features. HLA-F–positive patients had a significantly worse prognosis than HLA-F–negative patients (P = 0.012). However, HLA-F expression was not an independent prognostic factor in multivariate analysis. ConclusionsThe present study provides the first evidence that neo-HLA-F expression is of clinical significance in gastric adenocarcinoma. HLA-F expression in gastric adenocarcinoma may promote the aggressive behavior of tumors by suppressing the activity of antitumor immune effector cells.

PINCH expression and its clinicopathological significance in gastric adenocarcinoma.

Objective: Particularly interesting new cysteine-histidine rich protein (PINCH) is an important component of the local adhesion complexes and upregulated in several types of malignancies, and involved in the incidence and development of tumours. PINCH expression is also independently correlated with poorer survival in patients with colorectal cancer. However, there is no study of PINCH in gastric cancer, therefore, the aim of this project was to investigate PINCH expression and its clinicopathological significance in gastric adenocarcinoma. Patients and methods: PINCH expression was immunohistochemically examined in normal gastric mucous (n = 30) and gastric adenocarcinoma (n = 73), from gastric cancer patients. Results: PINCH expression in the associated-stroma of gastric cancers was heterogeneous, and its positive rate (75%) was higher than that of normal gastric mucosa (43%, X2 = 9.711, p = 0.002). The stronger staining was observed at the invasive edge of tumour when compared to the inner area of tumour. The rate of positive PINCH (88%) in the cases with lymph node metastasis was higher than that (52%) in the cases without metastasis (X2 = 11.151, p = 0.001). PINCH expression was not correlated with patients’ gender, age, tumour size, differentiation and invasion depth (p > 0.05). Comclusion: PINCH protein might play an important role in the tumourigenesis and metastasis of gastric adenocarcinoma.

PINCH Expression and Its Clinicopathological Significance in Gastric Adenocarcinoma

Objective: Particularly interesting new cysteine-histidine rich protein (PINCH) is an important component of the local adhesion complexes and upregulated in several types of malignancies, and involved in the incidence and development of tumours. PINCH expression is also independently correlated with poorer survival in patients with colorectal cancer. However, there is no study of PINCH in gastric cancer, therefore, the aim of this project was to investigate PINCH expression and its clinicopathological significance in gastric adenocarcinoma.Patients and methods: PINCH expression was immunohistochemically examined in normal gastric mucous (n= 30) and gastric adenocarcinoma (n= 73), from gastric cancer patients.Results: PINCH expression in the associated-stroma of gastric cancers was heterogeneous, and its positive rate (75%) was higher than that of normal gastric mucosa (43%,X2= 9.711,p= 0.002). The stronger staining was observed at the invasive edge of tumour when compared to the inner area of tumour. The rate of positive PINCH (88%) in the cases with lymph node metastasis was higher than that (52%) in the cases without metastasis (X2= 11.151,p= 0.001). PINCH expression was not correlated with patients’ gender, age, tumour size, differentiation and invasion depth (p&gt; 0.05).Comclusion: PINCH protein might play an important role in the tumourigenesis and metastasis of gastric adenocarcinoma.

Mechanism of vasculogenic mimicry and its clinicopathologic significance in gastric adenocarcinoma

Objective:To explore whether vasculogenic mimicry (VM) exists in gastric adenocarcinoma (GAC) and to investigate the clinicopathologic significance of VM in GAC.Methods:We tended to illuminate the mechanism of VM by performing immunohistochemical staining of MMP-2,MMP-9 and Cathepsin D.A total of 173 GAC samples with detailed follow -up data were collected.CD31/ periodic acid-Schiff (PAS) double staining and CK818 immunohistochemical staining were performed to validate the existence of VM in GAC.The values of MVD (microvascular density) and VMD (vasculogenic mimicry density) were counted respectively.Immunohistochemical staining of MMP-2,MMP-9 and Cathepsin D was performed for all samples.Results:VM was observed in 40 of the 173 GAC samples,especially in poorly differentiated GAC (P=0.014).Patients with VM were prone to hematogenous metastasis and distant recurrence compared with those without VM (P=0.020,0.029).Higher VMD count was also associated with hematogenous metastasis (P=0.003).There was not significant difference in MVD count between VM-positive and VM-negative groups (F=1.596,P=0.482).The Kaplan-Meier survival analysis showed that the survival duration of the VM-positive group was significantly shorter than that of VM-negative group (P=0.022).Cox proportional hazards model indicated that the VM and TNM stage were independent predictors for poor prognosis of GAC (P=0.039 and 0.004).The immunohistochemical expression of MMP-2,MMP-9 and Cathepsin D was higher in VM-positive group than in VM-negative group (P0.05).Conclusion:VM exists in GAC,especially in poorly differentiated GAC.VM is an unfavorable prognostic indicator for GAC.MMP-2,MMP-9 and Cathepsin D might involve the formation of VM in GAC.