Comparison of the mutation patterns between tumor tissue and cell-free DNA in stage IV gastric cancer

Compared to stage I-III gastric cancer (GC), the level of cell-free DNA (cfDNA) was significantly higher in stage IV GC. The mutation patterns of different metastatic patterns between cfDNA and tumor DNA in stage IV GC have not yet been reported. We used next-generation sequencing (NGS) to analyze cfDNA and tumor DNA in 56 stage IV GC patients. Tumor DNA and cfDNA were analyzed using a 29-gene NGS panel. In tumor samples, the most commonly mutated gene was TP53 (64%), followed by ARID1A (62%), KMT2C (60%) and KMT2D (58%). In cfDNA samples, the most commonly mutated genes were FAT4 (19%) and MACF1 (19%), followed by KMT2D (18%), ARID1A (14%) and LRP1B (14%). The concordance of mutation patterns in these 29 genes was 42.0% between cfDNA and tumor DNA. A specificity of 100% was found when using the mutation status of cfDNA to predict mutations in tumor samples. The sensitivity of the mutation status of cfDNA to predict mutation in tumor samples was highest in FAT4 (88.9%), followed by MACF1 (80%), CDH1 (75%) and PLB1 (75%). For cfDNA with PLB1 mutations, patients were more likely to develop distant lymphatic metastasis than peritoneal metastasis. Patients with multiple-site metastases had significantly more mutated spots than patients with single-site metastasis. Due to the high sensitivity and specificity of some genes in the prediction of mutation in tumor samples, monitoring the mutation pattern of cfDNA may be useful in the stage IV GC treatment.

The clinicopathological and genetic differences among gastric cancer patients with no recurrence, early recurrence, and late recurrence after curative surgery

BACKGROUND

To date, few reports have investigated the genetic alterations and clinicopathological features among gastric cancer (GC) patients with no tumor recurrence, early recurrence, and late recurrence following curative surgery.

METHODS

A total of 473 GC patients undergoing curative surgery were included. The clinicopathological characteristics, patient prognosis, recurrence patterns, and genetic alterations were compared between GC patients with early recurrence and late recurrence.

RESULTS

Among the 473 GC patients, 119 had early recurrence (<2 years) and 45 had late recurrence (≥2 years). Patients with early recurrence had tumor size larger than 5 cm, fewer superficial-type tumors, more lymphovascular invasion, more advanced pathological T and N categories and Tumor, Node, Metastasis (TNM) stages, and worse 5-year overall survival than patients with late recurrence and no recurrence. For intestinal-type GC, patients with no tumor recurrence had more Helicobacter pylori infection than patients with early recurrence and late recurrence; for diffuse-type GC patients, the frequency of PIK3CA amplification was the highest in early recurrence, followed by late recurrence and no recurrence. GC patients with single-site recurrence had more ARID1A mutations than those with multiple-site recurrence. Multivariate analysis demonstrated that age, tumor recurrence, and pathological N categories were independent prognostic factors.

CONCLUSION

PIK3CA amplifications were more common in diffuse-type GC with early recurrence, whereas ARID1A mutations were more common in patients with single-site recurrence. Targeted therapy and immunotherapy might be helpful for these patients.

Comparison of the Long-term Outcome Between Billroth-I and Roux-en-Y Reconstruction Following Distal Gastrectomy for Gastric Cancer

BACKGROUND

Various reconstruction methods have been performed following distal gastrectomy; however, each reconstruction method has its own advantages and disadvantages. This study aims to compare the long-term outcomes between Billroth-I (B-I) and Roux-en-Y (RY) reconstruction after distal gastrectomy for gastric cancer.

METHODS

A total of 459 patients who underwent distal gastrectomy (B-I: 166, RY: 293) were included. Postoperative endoscopic findings and biliary tract stone formation were compared between the two groups.

RESULTS

At 1 year and 2 years postoperatively, gastric residue was more common in the RY group, gastritis was similar between groups, and bile reflux was more common in the B-I group. At 5 years postoperatively, gastric residue was similar between the groups, while gastritis and bile reflux were more common in the B-I group. Gastroesophageal reflux was more common in the B-I group at 1 year postoperatively, but gastroesophageal reflux became not significantly different between the groups at 2 and 5 years postoperatively. Gallstone formation was more common in the RY group and in patients aged ≥ 65 years.

CONCLUSION

During long-term follow-up, RY reconstruction was associated with lower incidence of bile reflux and gastritis, and higher incidence of gallstone formation than B-I reconstruction. The incidence of gastric residue was more common in the RY reconstruction group in the early postoperative period and became not significantly different between the two groups over time. For aged patients with RY reconstruction, cholecystectomy is recommended concurrently as gastrectomy.

Cardia Gastric Cancer Is Associated With Increased PIK3CA Amplifications and HER2 Expression Than Noncardia Gastric Cancer According to Lauren Classification

Background

To date, few reports have investigated genetic alterations and clinicopathological features in cardia and noncardia gastric cancer (GC).

Methods

In total, 435 GC patients receiving curative surgery were included. The clinicopathological features, recurrence patterns, prognoses and genetic alterations were compared between cardia and noncardia GC patients.

Results

Among the 435 enrolled patients, 47 (10.8%) had cardia GC. Compared with noncardia GC, cardia GC was associated with more intestinal-type tumors and similar initial recurrence patterns and 5-year overall survival (OS; 50.8% vs. 50.5%, P = 0.480) and disease-free survival (DFS; 48.6% vs. 48.9%, P = 0.392) rates. For both intestinal-type GC and diffuse-type GC, the clinicopathological features and 5-year OS and DFS rates were not significantly different between the cardia and noncardia GC patients. Multivariable analysis showed that cardia GC was not an independent prognostic factor. Compared with noncardia GC, cardia GC was associated with increased PIK3CA amplification than in patients with intestinal-type GC and was associated with increased HER2 expression in patients with diffuse-type GC.

Conclusions

Cardia GC is not an independent prognostic factor. In cardia GC patients with intestinal-type GC, PIK3CA amplification was more common, and in those with diffuse-type GC, HER2 expression was more common. Targeted therapy may be beneficial for these patient subgroups.

Genetic alterations in gastric cancer patients according to sex

To date, few reports have investigated the genetic alterations and clinicopathological features in gastric cancer (GC) according to sex. In total, 2673 GC patients receiving curative surgery were enrolled. Among the 2673 GC patients, 1979 (74.0%) patients were male. After propensity-score matching, 846 patients were enrolled for the analysis, including 423 males and 423 females. There was no significant difference in the clinicopathological features between the sexes. Regarding the initial recurrence pattern, the males were more likely to develop tumor recurrence and liver metastasis than the females, especially in stage III GC. Regarding the molecular analysis, the males had higher PD-L1 expression than the females, especially in stage III GC. In addition, the patients aged ≥ 65 years had higher PD-L1 expression than the patients younger than 65 years. The multivariate analysis demonstrated that sex was among the independent prognostic factors affecting overall survival (OS) and disease-free survival (DFS). Among the patients with liver metastases, PD-L1 expression was more common among the aged male patients. The males were associated with more tumor recurrence and higher PD-L1 expression than the females, especially in stage III GC. For GC patients with liver metastases, PD-L1 testing is recommended, especially among aged male patients.

Hyper-viscoelastic mechanical behavior of cranial pia mater in tension

BACKGROUND

Cranial pia mater, the innermost layer of the meninges, protects the central nervous system by tightly wrapping the brain and damping the external impact force to the brain. Accurate experimental data of the mechanical property of the cranial pia mater can enhance the theoretical prediction of traumatic brain injury or the scientific surgery design for brain disease. The aim of this study is to characterize the mechanical behavior of the cranial pia mater.

METHODS

In vitro tensile and stress-relaxation experiments of ovine cranial pia mater specimens were conducted at eight strain rates to characterize the rate-dependent viscoelastic property. The tensile and stress-relaxation experimental data were fitted by an Ogden hyper-viscoelastic model with a strain rate function to describe the mechanical behavior of the cranial pia mater.

FINDINGS

The elastic modulus and the ultimate stress are significantly increased from 5.545 MPa and 0.535 MPa at 0.00167 s^-1 to 18.345 MPa and 2.547 MPa at 0.83 s^-1 (p < .0001), respectively. The initial stress and the long-term stress (300 s) are also increased significantly with the increasing strain rates (p < .0001). A good fit of the experimental data with the Ogden hyper-viscoelastic model incorporated with a strain rate function was achieved (R² > 0.93).

INTERPRETATION

The cranial pia mater exhibits as a rate-dependent hyper-viscoelastic material in the tensile and stress-relaxation experiments. Compared with the brain, the stiffer nature of the cranial pia mater indicates its essential role in brain protection. The rate-dependent constitutive model provides a proper description of the hyper-viscoelastic characteristics of the cranial pia mater in tension and may provide a basic constitutive relationship for numerical simulations of traumatic brain injury.

The clinicopathological characteristics and genetic alterations between younger and older gastric cancer patients with curative surgery

Few reports have investigated different genetic alterations according to age in various cancers. In total, 1749 GC patients receiving curative surgery were enrolled. The clinicopathological features, and prognoses were compared between younger (<65 years) and older (≥65 years) patients. Genetic mutations were analyzed using mass spectrometric single nucleotide polymorphism genotyping technology, including 68 validated mutations within eight genes (TP53, ARID1A, BRAF, and the PI3K/AKT pathway) previously reported in relation to age. Younger patients were more likely to be female and have poor cell differentiation, diffuse-type tumors, less lymphovascular invasion, fewer liver metastases, and better 5-year overall survival (OS) (68.0% vs. 54.6%, P<0.001) and disease-free survival (DFS) (65.4% vs. 53.0%, P<0.001) rates than older patients. Regarding the genetic alterations, older patients had more microsatellite instability-high (MSI-H) tumors and more ARID1A mutations than younger patients. Younger patients had significantly better OS and DFS rates than older patients for each pathological Tumor, Node, Metastasis (TNM) stage. Older patients had a significantly higher non-cancer related death rate than younger patients (36.2% vs. 12.3%, P<0.001). Age was an independent prognostic factor in GC. In conclusion, age was associated with different clinicopathological features and genetic alterations in GC with curative surgery.

The clinicopathological characteristics and prognosis of patients with node-positive gastric cancer after curative surgery

BACKGROUND

Lymph node (LN) metastasis is one of the independent prognostic factors of gastric cancer (GC). The difference in survival rates and initial recurrence patterns in patients with node-positive GC with retrieved LN numbers greater than or less than 16 is worthy of further study.

METHODS

A total of 1314 patients with node-positive GC were enrolled. The clinicopathological characteristics, retrieved LN numbers, adjuvant chemotherapy, initial recurrence patterns, and survival differences between serosa-negative and serosa-positive GC were investigated.

RESULTS

For serosa-negative GC, patients with retrieved LN numbers ≥16 were associated with fewer tumor recurrences, locoregional recurrences, distant metastases, and better 5-year overall survival (OS) rates and disease-free survival (DFS) rates. For serosa-positive GC, patients with retrieved LN numbers ≥16 were associated with similar locoregional and distant metastasis and similar 5-year OS and DFS rates compared with those with retrieved LN numbers <16. Retrieved LN numbers fewer than 16 can cause stage migration compared with retrieved LN numbers ≥16. Multivariate analysis showed that both the retrieved LN numbers (≥ or <16) and adjuvant chemotherapy were independent prognostic factors affecting OS in serosa-negative GC, while adjuvant chemotherapy but not the retrieved LN numbers was an independent prognostic factor of OS in serosa-positive GC.

CONCLUSION

For serosa-negative GC, retrieved LN numbers fewer than 16 can cause stage migration, a higher tumor recurrence rate and worse OS and DFS rates compared with patients with retrieved LN numbers ≥16. Due to a high tumor recurrence rate in serosa-positive GC, adjuvant chemotherapy rather than retrieved LN numbers played an important role in improving patient prognosis.

The Clinicopathological Features and Genetic Alterations in Epstein-Barr Virus-Associated Gastric Cancer Patients after Curative Surgery

Background: Epstein–Barr virus (EBV)-associated gastric cancer (GC) is one of four major gastric cancer types and is traditionally considered to be related to lymphoepithelioma-like GC. Few studies have investigated the clinical significance of EBV infection in intestinal/solid type, diffuse (poorly cohesive) type, and lymphoepithelioma-like GC. Methods: A total of 460 GC patients receiving curative surgery were enrolled. The clinicopathological features, genetic alterations and prognoses were compared between patients with and without EBV infection. Results: EBV-positive GC patients (n = 43) had more tumors located in the upper and middle stomach, more common in lymphoepithelioma-like carcinoma, more lymphoid stroma, fewer Helicobacter pylori infections, and higher programmed death-ligand 1 (PD-L1) expression than EBV-negative GC patients. For intestinal/solid type GC, EBV-positive tumors were more likely to be located in the upper and middle stomach, have more lymphoid stroma, fewer Helicobacter pylori infections, higher PD-L1 expression, and more liver metastases than EBV-negative tumors. For diffuse (poorly cohesive) type GC, EBV-positive tumors were more likely to be located in the upper stomach, and have more lymphoid stroma than EBV-negative tumors. For lymphoepithelioma-like GC, EBV-positive tumors had more PI3K/AKT pathway mutations than EBV-negative tumors. Conclusions: Intestinal/solid type GC patients with EBV-positive tumors were associated with higher PD-L1 expression and more liver metastases, while lymphoepithelioma-like GC patients with EBV-positive tumors had more PI3K/AKT pathway mutations. Immunotherapy and targeted therapy may be beneficial for these groups of patients. Routine EBV survey is recommended in GC.

Prognosis and clinicopathologic features in patients with gastric stump cancer after curative surgery

Background

Gastric stump ("remnant") cancer is the development of a malignancy related to previous gastric surgery. Prognosis in gastric stump cancer, compared with that in primary gastric cancer, is still controversial.

Methods

From January 1988 to December 2012 at a single medical centre in Taiwan, 105 patients with gastric stump cancer, including 85 with previous peptic ulcer disease and 20 with previous gastric cancer, were analyzed for clinicopathologic characteristics and overall survival (os).

Results

The 5-year os rates for patients with gastric stump cancer and with primary gastric cancer were 51.2% and 54.5% respectively (p = 0.035). Analysis of clinicopathologic characteristics indicated that, compared with patients having primary gastric cancer, those with gastric stump cancer had more lymph node metastasis (p < 0.001) and had been diagnosed at a more advanced stage (p = 0.047). Multivariate analysis with os as an endpoint showed that age [p = 0.015; hazard ratio (hr): 2.300; 95% confidence interval (ci): 1.173 to 4.509], tumour size (p = 0.037; hr: 1.700; 95% ci: 1.031 to 2.801), stromal reaction (p = 0.021; hr: 1.802; 95% ci: 1.094 to 2.969), and pathologic N category (p = 0.001; hr: 1.449; 95% ci: 1.161 to 1.807) were independent predictors in gastric stump cancer. The os rates for patients with gastric stump cancer who previously had gastric cancer or peptic ulcer disease were 72.9% and 50.0% respectively (p = 0.019). The Borrmann classification was more superficial (p = 0.005), lymph node metastases were fewer (p = 0.004), and staging was less advanced (p = 0.025) in patients with gastric stump cancer who previously had gastric cancer than in their counterparts who previously had peptic ulcer disease.

Conclusions

Survival is poorer in patients with gastric stump cancer who previously had peptic ulcer disease than in those who previously had primary gastric cancer. Patients with gastric stump cancer who previously had gastric cancer and could receive curative gastrectomy tended to have a better prognosis because of a more superficial Borrmann classification. Regular follow-up in patients who have undergone gastric surgery is recommended for the early detection of gastric stump cancer.

The clinicopathological characteristics and genetic alterations of mucinous carcinoma of the stomach

BACKGROUND

Mucinous gastric carcinoma (MGC) is rare and often associated with an advanced stage. The clinicopathological features and prognosis of MGC and non-MGC (NMGC) are controversial.

METHODS

In total, 2637 gastric cancer (GC) patients receiving curative surgery were enrolled. The clinicopathological features and genetic alterations were compared between patients with MGC and NMGC.

RESULTS

Among the 2637 GC patients, 92 (3.5%) had MGC. After propensity score matching, compared to patients with NMGC, patients with MGC had more poorly differentiated tumors, medullary stromal reaction-type tumors, tumors with infiltrating Ming's classification, diffuse-type tumors, more abnormal preoperative serum carbohydrate antigen 19-9 levels, and more advanced T categories. After propensity score matching, there were no significant differences between MGC and NMGC regarding the initial recurrence patterns, 5-year overall survival (OS), and disease-free survival (DFS) rates. Multivariate analysis demonstrated that the MGC cell type is not an independent prognostic factor of OS and DFS. No significant differences in microsatellite instability status, Epstein-Barr virus infection, Helicobacter pylori infection, or genetic mutations were observed between MGC and NMGC. The expression of programmed death-ligand 1 (PD-L1) was significantly higher in MGC than that in NMGC. MGC was diagnosed at a more advanced stage compared with NMGC.

CONCLUSION

MGC itself was not an independent prognostic factor of worse survival. MGC was correlated with higher PD-L1 expression than NMGC, which may have a clinical impact on the treatment of MGC in the future.

Analysis of the clinical significance of DNA methylation in gastric cancer based on a genome-wide high-resolution array

BACKGROUND

Aberrant DNA methylation is involved in gastric carcinogenesis and may serve as a useful biomarker in the diagnosis and detection of gastric cancer (GC) recurrence.

RESULTS

A total of 157 patients who received surgery for GC were enrolled in the present study. A genome-wide methylation analysis was performed in tumor and adjacent normal tissues for the discovery set of 16 GC patients; the top three hypermethylated CpG sites of DNA promoters were selected for validation in tissue and plasma samples for the validation set of 141 GC patients. The frequencies of the top three hypermethylated genes in available patient tissues (n = 141) and plasma samples (n = 106) were 41.8% and 38.7%, respectively, for ADAM19; 40.4% and 42.5%, respectively, for FLI1; and 56.7% and 50.9%, respectively, for MSC. In both tissue and plasma samples, FLI1 hypermethylation was associated with more advanced GC and liver and distant lymphatic metastasis, and ADAM19 hypermethylation was associated with more stage IV GC. In plasma samples, MSC hypermethylation was more common in non-superficial type GC than samples without MSC hypermethylation. In both tissue and plasma samples, patients with methylation of all the three genes had significantly more liver metastases, distant lymphatic metastases, and paraaortic lymph node metastases than patients with two or fewer hypermethylated genes. The survival analysis showed that only for stage III GC, patients with hypermethylation of two or three genes had a worse 5-year disease-free survival rate than those with hypermethylation of one or none of the three genes. Subgroup analysis showed that FLI1 hypermethylation in both tissue and plasma samples was associated with liver metastasis in MSI-/EBV- GC, and MSC hypermethylation in tissue samples was correlated with liver metastasis in MSI+ or EBV+ GC. Patients with FLI1 hypermethylation in plasma samples had a significantly worse 5-year disease-free survival rate than those without FLI1 hypermethylation in MSI-/EBV- GC. FLI1 hypermethylation was an independent prognostic factor affecting the overall survival and disease-free survival in both tissue and plasma samples.

CONCLUSIONS

DNA methylation is a useful biomarker for predicting tumor recurrence patterns and GC patient survival.

Clinicopathological differences in signet ring cell adenocarcinoma between early and advanced gastric cancer

BACKGROUND

Signet ring cell adenocarcinoma is a histological classification based on the WHO classification. The presence of this specific histological type is associated with a worse pathological appearance. The prognosis of signet ring cell adenocarcinoma in gastric cancer patients after curative surgery is still under debate.

METHODS

From January 1988 to December 2012, a total of 2971 patients, including 819 early and 2152 advanced gastric cancer patients underwent curative resection for gastric cancer. Among them, there were 185 cases of signet ring cell adenocarcinoma in early gastric cancer patients, while there were 570 cases in advanced gastric cancer patients.

RESULTS

The overall incidence of signet ring cell adenocarcinoma was 25.4%. Our results showed that the 5-year overall survival rates of early gastric cancer patients with signet ring cell adenocarcinoma and non-signet ring cell adenocarcinoma were 90.7 and 83.2%, respectively (P = 0.001). The 5-year disease-free survival rates of early gastric cancer patients with signet ring cell adenocarcinoma and non-signet ring cell adenocarcinoma were 87.4 and 81.6%, respectively (P = 0.003). The 5-year overall survival rates of advanced gastric cancer patients with signet ring cell adenocarcinoma and non-signet ring cell adenocarcinoma were 32.1 and 37.9%, respectively (P = 0.041). The 5-year disease-free survival rates of advanced gastric cancer patients with signet ring cell adenocarcinoma and non-signet ring cell adenocarcinoma were 28.6 and 35.2%, respectively (P = 0.037). Signet ring cell adenocarcinoma was an independent predictor for overall survival in advanced gastric cancer (P = 0.017).

CONCLUSION

The clinical features and prognosis of signet ring cell adenocarcinoma are different between early and advanced gastric cancer. Signet ring cell adenocarcinoma is a poor prognostic factor in advanced gastric cancer after curative resection.

Comparison of the Clinicopathological Characteristics and Genetic Alterations Between Patients with Gastric Cancer with or Without Helicobacter pylori Infection

BACKGROUND

Helicobacter pylori (HP) can induce epithelial cells and intestinal metaplasia with genetic damage that makes them highly susceptible to the development of gastric cancer (GC).

MATERIALS AND METHODS

Between 2005 and 2010, 356 patients with gastric cancer who received curative surgery were enrolled. Analysis of HP, Epstein-Barr virus (EBV) infection, PIK3CA amplification, and mutation analysis of 68 mutations in eight genes using a mass spectrometric single-nucleotide polymorphism genotyping technology was conducted. The clinicopathological characteristics of patients with or without HP infection were compared.

RESULTS

Among the 356 patients, 185 (52.0%) had HP infection. For intestinal-type GC, patients with HP infection were more likely to be younger and had fewer PI3K/AKT pathway genetic mutations than those without HP infection. For diffuse-type GC, patients with HP infection were characterized by less male predominance, less lymphoid stroma, fewer microsatellite instability-high tumors, and fewer PI3K/AKT pathway genetic mutations than those without HP infection. Patients with HP infection had less tumor recurrence and a better 5-year overall survival (87.7% vs. 73.9%, p = .012) and disease-free survival (64.1% vs. 51.3%, p = .013) than those without HP infection, especially for intestinal-type GC. For EBV-negative GC, patients with HP infection had fewer PI3K/AKT pathway mutations and a better 5-year overall survival and disease-free survival than those without HP infection. Multivariate analysis demonstrated that HP infection was an independent prognostic factor regarding overall survival and disease-free survival.

CONCLUSION

Patients with GC with HP infection were associated with fewer PI3K/AKT pathway genetic mutations and better survival than those without HP infection, especially for EBV-negative and intestinal-type GC.

IMPLICATIONS FOR PRACTICE

Patients with gastric cancer with Helicobacter pylori (HP) infection had fewer PI3K/AKT pathway genetic mutations, less tumor recurrence, and better survival than those without HP infection, especially for Epstein-Barr virus (EBV)-negative and intestinal-type gastric cancer. HP infection is an independent prognostic factor regarding overall survival and disease-free survival. Future in vivo and in vitro studies of the correlation among HP infection, PI3K/AKT pathway, and EBV infection in gastric cancer are required.

The Clinical Implication of PTEN and FAK Expression in Gastric Cancer Patients

Objective:

The tumor suppressor gene phosphatase and tensin homolog (PTEN) was reported to inhibit the growth and invasion of gastric cancer (GC) via the downregulation of focal adhesion kinase (FAK). To date, the clinical implication of PTEN and FAK expression in GC has not been well addressed.

Methods:

A total of 200 GC patients receiving curative surgery were enrolled. The clinicopathologic features according to the expression of PTEN and FAK protein using immunohistochemical staining were compared among patients.

Results:

Patients with high PTEN expression were more likely to have smaller tumor size, more well- and moderately differentiated tumors, a more superficial gross appearance, less scirrhous stromal reactions, more likely to have high FAK expression, and have less advanced pathologic tumor (T) category, node (N) category, and tumor, node, metastasis (TNM) stage and more distant metastases than patients with low PTEN expression. Multivariate analysis showed that PTEN/FAK expression status is an independent prognostic factor affecting overall survival (OS) and disease-free survival (DFS). Patients with PTEN(high)/FAK(low) had better OS and DFS, followed by those with PTEN(high)/FAK(high), those with PTEN(low)/FAK(low), and those with PTEN(low)/FAK(high) (OS: 83.3% versus 58.0% versus 46.2% versus 26.5%, respectively, P &lt; 0.001; DFS: 83.3% versus 55.8% versus 30.8% versus 24.4%, respectively, P &lt; 0.001).

Conclusions:

GC patients with high PTEN expression were more likely to have fewer tumor recurrences and a better prognosis than those with low PTEN expression. PTEN and FAK may have opposing effects on GC patient survival. Our results may have clinical impact on treatment of GC patients.

Correlation between HGF/c-Met and Notch1 signaling pathways in human gastric cancer cells

In recent decades, research concerning gastric carcinogenesis has rapidly progressed. It is evident that hepatocyte growth factor (HGF) is clinically related to gastric cancer progression and metastasis. In addition, previous studies have found that expression of Notch ligand Jagged1 is correlated with the poor prognosis of gastric cancer. However, the interaction between the HGF/c-Met and Notch1 signaling pathways remains unknown. In the present study, we found that gastric cancer patients with positive c-Met expression exhibited poorer overall survival than patients without c-Met expression (P=0.043) and that Jagged1 expression was significantly correlated with c-Met expression (r=0.301; P=0.004) in human gastric cancer specimens. In addition, Jagged1 activity increased after HGF stimulation, which in turn increased the downstream expression of cyclooxygenase 2 (COX-2) in a time-dependent manner. After knockdown of Notch1 intracellular domain (N1IC), HGF was found to increase the proliferation and migration ability in human gastric cancer cells. However, overexpression of N1IC still had no effect after HGF stimulation. Our study found a feedback loop between HGF/c-Met and Jagged1/Notch1 signaling. Furthermore, both HGF/c-Met and Notch1 signaling triggered COX-2 activity. These results suggest that gastric cancer progression is not associated with a unique signaling pathway and that a feedback loop may exist between the HGF/c-Met and Notch1 signaling pathways, which may result in therapeutic resistance. Therefore, multi-modality therapies should be considered for treating gastric cancer.

MicroRNA-23a/27a/24-2 cluster promotes gastric cancer cell proliferation synergistically

Previous studies have indicated that certain microRNAs (miRNAs/miRs) function as either tumor suppressors or oncogenes in human cancer. The present study identified the miR-23a/27a/24-2 cluster, containing miR-23, miR-27a and miR-24, as an oncogene in gastric cancer. The expression of the miR-23a/27a/24-2 cluster was upregulated in clinical gastric cancer tissues. Transfection with inhibitors of miR-23a, miR-27a, or miR-24, either independently or together, repressed in vitro colony formation and in vivo tumor formation. The miR23a/27a/24-2 cluster inhibitors repressed the growth of gastric cancer cells in a synergistic manner. In addition, treatment with lower doses of the miRNA inhibitor mixture induced the formation of apoptotic bodies. According to computational predictions using TargetScan, suppressor of cytokine-induced signaling 6 (SOCS6) was identified as one of the downstream target genes of the miR-23a/27a/24-2 cluster. The expression of SOCS6 was significantly lower in tumor tissues than in matched normal tissues (P<0.01) and was associated with poor survival (P<0.00001). Taken together, these results strongly suggested that the miR-23a/27a/24-2 cluster may mediate the progression of gastric cancer through the suppression of SOCS6 expression. The present study also provides a novel molecular target for the development of an anti-gastric cancer agent.

Caspase-3, a key apoptotic protein, as a prognostic marker in gastric cancer after curative surgery

BACKGROUND

Caspase-3 acts as a major executioner protein in proteolytic degradation during apoptosis. The role of Caspase-3 in gastric cancer remains controversial.

METHODS

A total of 366 gastric cancer patients who received curative surgery were enrolled. Caspase-3 expression in gastric tumors was examined by immunohistochemical staining. Correlations between Caspase-3 expression and the survival rates and between Caspase-3 expression and the clinicopathological parameters of the gastric cancer patients were analyzed.

RESULTS

The 5-year overall survival rates of gastric cancer patients with and without Caspase-3 expression were 51.2% and 37.3%, respectively (P = 0.030). The 5-year disease-free survival rates of gastric cancer patients with and without Caspase-3 expression were 49.2% and 34.6%, respectively (P = 0.029). Analyses of the clinicopathological features showed that larger tumor size (P = 0.030), more advanced Borrmann type (P = 0.012), more aggressive stromal reaction (P = 0.001), higher classification using Ming's infiltrating histology type (P = 0.018), more lymph node involvement (P = 0.019), and more lymphovascular involvement (P = 0.045) were significantly correlated with a lack of Caspase-3 expression. The multivariate analysis showed that age (P = 0.001), Borrmann classification (P = 0.032), stromal reaction type (P = 0.018), TNM pathological T category (P = 0.002), TNM pathological N category (P < 0.001), and Caspase-3 expression (P = 0.041) were significantly correlated with the overall survival of gastric cancer patients.

CONCLUSION

Caspase-3 expression in gastric cancer patients is related to favorable clinicopathological features and a positive prognosis after curative surgery. Caspase-3 may act as a tumor suppressor in human gastric cancer.

PARP-1 Involvement in Autophagy and Their Roles in Apoptosis of Vascular Smooth Muscle Cells under Oxidative Stress

Autophagy and poly(ADP-ribose) polymerase 1 (PARP-1) are activated and involved in a series of cell processes under oxidative stress, which is associated with pathogenesis of atherosclerosis. Research on their relationship under oxidative stress has been limited. In this study, we aimed to investigate the activation, relationship, and role of autophagy and PARP-1 in vascular smooth muscle cell (VSMC) death under oxidative stress. This study explored the signal molecule PARP-1 and autophagy in VSMCs using gene silencing and the hydrogen peroxide (H2O2)-stimulated oxidative stress model. We observed that H2O2 could induce autophagy in VSMCs, and the inhibition of autophagy could protect VSMCs against oxidative stress-mediated cell death. Meanwhile, PARP-1 could also be activated by H2O2. Additionally, we analysed the regulatory role of PARP-1 in oxidative stress-mediated autophagy and found that PARP-1 was a novel factor involved in the H2O2-induced autophagy via the AMPK-mTOR pathway. Finally, PARP-1 inhibition protected VSMCs against caspase-dependent apoptosis. These data suggested that PARP-1 played a critical role in H2O2-mediated autophagy and both of them were involved in apoptosis of VSMCs.

A pilot study of lymph node mapping with indocyanine green in robotic gastrectomy for gastric cancer

OBJECTIVES

Robotic gastrectomy has become increasingly popular in the treatment of gastric cancer, especially in Asian countries. The use of indocyanine green fluorescence has been reported in lymphatic mapping for gastric cancer in laparoscopic gastrectomy; however, there have been few reports regarding the use of indocyanine green in robotic gastrectomy.

METHODS

From January 2011 to March 2016, a total of 79 patients underwent robotic gastrectomy for gastric cancer. Among them, intraoperative subserosal injection (n = 9) or preoperative submucosal injection (n = 5) of indocyanine green with near-infrared imaging was performed in 14 patients, and the other 65 patients underwent robotic gastrectomy without the use of indocyanine green.

RESULTS

There was no significant difference in the operative time, total number of retrieved lymph nodes, operative blood loss, and postoperative hospital stay between the patients who underwent robotic gastrectomy with or without indocyanine green fluorescence. For each lymph node station, there was significantly more number of retrieved lymph nodes in the indocyanine green group than in the no-indocyanine green group at the greater curvature side of the low body (#4d) to the infrapyloric region (#6) of the stomach. Five of the 14 patients who received an indocyanine green injection for lymphatic mapping had lymph node metastasis, and metastatic lymph nodes were located in the lymph node stations as detected by indocyanine green fluorescence during surgery.

CONCLUSION

Indocyanine green fluorescence with near-infrared imaging is feasible and is a promising method of lymphatic mapping in robotic gastrectomy for gastric cancer. In future studies, larger patient numbers and long-term follow-up are required.

Comparison of the surgical outcomes of minimally invasive and open surgery for octogenarian and older compared to younger gastric cancer patients: a retrospective cohort study

Background

As life expectancy continues to increase around the world, the use of minimally invasive surgery (MIS) could be beneficial for octogenarian and older gastric cancer patients.

Methods

A total of 359 gastric cancer patients who underwent curative surgery between March 2011 and March 2015 were enrolled; 80 of these patients (22.2%) were octogenarians and older. Surgical approaches included MIS (50 laparoscopic and 65 robotic) and open surgery (n = 244). Surgical outcomes of MIS and open surgery in octogenarian and older patients were compared with younger patients.

Results

Among octogenarian and older patients, relative to open surgery (n = 53), MIS (n = 27) was associated with less operative blood loss, a shorter postoperative hospital stay and similar rates of surgical complications and mortality. For MIS (n = 115), octogenarian and older patients exhibited similar postoperative outcomes to those of younger patients. For open surgery (n = 244), relative to younger patients, octogenarian and older patients experienced longer postoperative hospital stays, a higher rate of wound infection and a higher incidence of pneumonia.

Conclusions

MIS for gastric cancer is beneficial and can be performed safely in octogenarian and older patients.

Urine miR-21-5p as a potential non-invasive biomarker for gastric cancer

Many reports have implicated that microRNAs involve in cancer development and progression, such as miR-155 in breast cancers and miR-196 in gastric cancers. Furthermore, microRNAs are more stable than typical protein-coding gene mRNAs in varieties of clinical samples including body fluids. This suggests that they are potentially valuable biomarkers for cancer monitoring. In this study, we have used urine samples of gastric cancer patients to demonstrate the feasibility of urine microRNAs for gastric cancer detection. Urine samples of gastric cancer patients were extracted for total RNA, which were examined for the expression of miR-21-5p using quantitative stem-loop PCR. Our results demonstrated that miR-21-5p could be detected in small amounts of urine samples with good stability, and the expression levels of miR-21-5p were reduced following surgical removal of gastric cancer tissues. These results implicate that urine miR-21-5p could be utilized as a novel non-invasive biomarker of gastric cancer detection and monitoring.

Mutations in PI3K/AKT pathway genes and amplifications of PIK3CA are associated with patterns of recurrence in gastric cancers

Mutations in genes involved in the PI3K/AKT pathway and amplifications of the PIK3CA gene in gastric cancer and their associations with clinicopathological characteristics and EBV infection were analyzed in this study. A total of 431 patients with gastric adenocarcinomas were enrolled, and 39 mutation hotspots were evaluated in these patients using MALDI-TOF mass spectrometry were analyzed. PIK3CA amplifications were analyzed using real-time quantitative PCR. Regarding patients with intestinal-type gastric cancer, those with mutations in PI3K/AKT pathway genes were also more likely to have tumors located in the lower-third of the stomach than were those without mutations. Regarding patients with diffuse-type gastric cancer, those with PI3K/AKT pathway mutations were more likely to have tumors located in the upper-third of the stomach and to have more hematogenous metastases, particularly in the liver and lungs, than were patients without such mutations (22.2% vs. 4.5%). No significant survival difference was observed between patients with vs. without PI3K/AKT pathway mutations. Mutations in PI3K/AKT pathway genes were associated with hematogenous metastasis in patients with diffuse-type gastric cancer. Only when the tumors were located in the middle-third of stomach, tumor with mutations of the PIK3CA gene or mutations of the PI3K/AKT pathway genes were associated with more EBV infection than those without mutations. Patients with PIK3CA amplifications were more likely to have diffuse-type and poorly differentiated gastric cancers and were more likely to experience peritoneal recurrence compared with those without PIK3CA amplifications. Even upon subgroup analysis, PI3KCA amplifications were found to not affect the patients’ outcomes.

Effects of Scutellaria baicalensis Georgi on Macrophage-Hepatocyte Interaction Through Cytokines Related to Growth Control of Murine Hepatocytes

The aim of this study is to elucidate the effects of Scutellaria baicalensis Georgi (SbG) extract and its constituents on macrophage-hepatocyte interaction in primary cultures. By using trans-well primary Kupffer cell culture or conditioned medium (CM) from murine macrophage RAW264.7 cell line (RAW cells), effects of SbG on hepatocyte growth were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide and trypan blue exclusion assay. Cytokine production, antibody-neutralization studies, and molecular mechanisms of transforming growth factor (TGF)-β1 gene expression were elucidated on SbG-treated RAW264.7 cells. In addition, recombinant human TGF-β1 (r-human TGF-β1) was added to elucidate the mechanisms of SbG effects on cultured hepatocytes. Immunohistochemistry using anti-NF-κB antibody was used to determine the possible signal transduction pathways in primary hepatocyte culture. The results showed that SbG stimulated the proliferation of cultured hepatocytes, possibly through NF-κB, but not of Toll-like receptor 4 activation; whereas SbG-RAW-CM and SbG in trans-well significantly suppressed the proliferation of hepatocytes. Antibody-neutralization studies revealed that TGF-β1 was the main antimitotic cytokine in SbG-treated RAW cells CM. The growth stimulation effect of SbG on cultured hepatocytes was inhibited by exogenous administration of r-human TGF-β1. Furthermore, SbG induced NF-κB translocation into the nuclei of cultured cells. In the RAW264.7 line, SbG and baicalin stimulated TGF-β1 gene expression via NF-κB and protein kinase C activation. We conclude that SbG stimulates hepatocyte growth via activation of the NF-κB pathway and induces TGF-β1 gene expression through the Kupffer cell–hepatocyte interaction, which subsequently results in the inhibition of SbG-stimulated hepatocyte growth.

Advances in Laparoscopic and Robotic Gastrectomy for Gastric Cancer

Robot-assisted gastrectomy has been reported to be a safe alternative to both conventional laparoscopy and the open approach for treating early gastric carcinoma. Currently, there are a limited number of published reports on this technique in the literature. We assessed the current status of robotic and laparoscopic surgery in the treatment of gastric cancer and compared the operative outcomes, learning curves, and oncological outcome of the two approaches. Robotic gastrectomy offers benefits that include increased ease of performing D2 lymph node dissection and reduced blood loss compared with laparoscopic gastrectomy. However, the operative time is longer, and robotic gastrectomy is more costly for the patients. Regarding to the operative and oncological outcomes, there appears to be no significant differences between laparoscopic and robotic gastrectomies after the surgeon overcomes the associated learning curves. Sharing the available knowledge regarding laparoscopic and robotic gastrectomies could shorten these learning curves. For elder patients, minimally invasive surgery that decreases the postoperative recovery time should be considered the preferred treatment. Prospective randomized studies are required to compare the surgical and oncological outcomes among laparoscopic, robotic, and open surgeries for both early and advanced gastric cancer.

The Correlation Between RhoA Expression and Clinicopathological Characteristics in Gastric Cancer Patients After Curative Surgery

BACKGROUND

The expression of RhoA, a member of the ras homologue family, is reported to be involved in tumorigenesis in some cancers; however, its prognostic value in gastric cancer is controversial.

METHODS

Between April 1988 and January 2005, a total of 206 gastric cancer patients receiving curative surgery were enrolled in this study. Immunohistochemical staining of the RhoA protein was performed, and the clinicopathological characteristics and initial recurrence patterns were compared between low RhoA expression (n = 55) and high RhoA expression (n = 151) gastric cancer patients.

RESULTS

For intestinal-type (n = 134) gastric cancer, there is no significant difference between the clinicopathological characteristics and RhoA expression. However, for diffuse-type (n = 82) gastric cancer, high RhoA expression was associated with more advanced pathological N category compared to low RhoA expression. A multivariate analysis revealed that age, pathological T and N categories, and RhoA expression were independent prognostic factors for overall survival after curative surgery. For all patients, the five-year overall survival rates and disease-free survival rates were higher in patients with low RhoA expression compared to those with high RhoA expression, which was observed in diffuse-type gastric cancer, not in intestinal-type gastric cancer. With regard to the initial recurrence pattern, patients with high RhoA expression had more distant metastasis compared to those with low RhoA expression, especially more liver metastasis.

CONCLUSIONS

RhoA expression is an independent prognostic factor for gastric cancer, especially for diffuse-type. We should be aware of liver metastasis during the follow-up of gastric cancer with high RhoA expression.

Clinical significance of circulating plasma DNA in gastric cancer

With the progression of molecular techniques, the detection of circulating plasma DNA (cpDNA) is clinically feasible. However, the role of the cpDNA levels in gastric cancer is not well understood. This study assessed the mutational profile in primary tumors and clarified the clinical utility of quantitative and qualitative cpDNA alterations in 277 patients with advanced gastric cancer. The concentrations of cpDNA were measured by TaqMan qPCR, and 68 mutations in 8 genes were studied for cpDNA mutations. The median cpDNA concentrations in patients with stages I, II, and III gastric cancer were 3979, 3390 and 4278 copies/mL, respectively, and increased to 11,380 copies/mL in patients with Stage IV gastric cancer (p < 0.001). Among the 35 patients harboring cpDNA mutations, Stage IV patients (100%) were more likely to display high cpDNA levels than were Stage I (33.3%), II (75%) and III patients (66.7%) (p = 0.037). Patients displaying high cpDNA levels were more likely to experience peritoneal recurrence and exhibited significantly lower 5-year overall survival rates (39.2% vs. 45.8%, p = 0.039) than did patients displaying low cpDNA levels. Only for late stage (Stages III or IV) gastric cancer, patients harboring cpDNA mutations were more likely to experience vascular invasion (20% vs. 2.4%, p = 0.036) and exhibited a lower 5-year overall survival rate than did those lacking cpDNA mutations (5.6% vs. 31.5%, p = 0.028). High cpDNA levels are associated with peritoneal recurrence and poor prognosis in patients with advanced gastric cancer; harboring cpDNA mutations is associated with poor prognosis among patients with late stage gastric cancer.

Adiabatic light transfer in titanium diffused lithium niobate waveguides

We report on the realization of adiabatic light transfer in lithium niobate (LiNbO₃) waveguides. This peculiar adiabatic tunneling scheme was implemented in a three-waveguide coupling configuration with the intermediate waveguide being inclined with respect to the outer waveguides to facilitate the adiabatic passage process. We have investigated and determined the adiabatic conditions of the LiNbO₃ device in terms of the structure configuration of the waveguide system and found optimal structure parameters by both simulation and experimental approaches. Broadband adiabatic couplings of bandwidth ~456 and 185 nm and peak coupling efficiencies of >0.96 have been obtained with a 2-cm long device for TE- and TM-polarized fundamental modes, respectively. Longer (5 cm) devices were also studied and found to be useful in increasing the adiabaticity of the device, especially for the TM-polarized mode.

Incidence of and Risk Factors for Tuberculosis (TB) in Gastric Cancer Patients in an Area Endemic for TB: A Nationwide Population-based Matched Cohort Study

To date, there have been few reports investigating the relationship between tuberculosis (TB) and gastric cancer.We conducted a nationwide population-based matched cohort study using data retrieved from Taiwan's National Health Insurance Research Database to determine the incidence of and risk factors for TB in patients diagnosed with gastric cancer. From 2000 to 2011, we identified 36,972 gastric cancer patients and normal subjects from the general population matched for age, sex, and comorbidities at a 1:1 ratio. The data were analyzed using Cox proportional hazards models.Compared with the matched cohort, gastric cancer patients exhibited a higher risk for TB (adjusted hazard ratio [HR] 2.25, 95% confidence interval [CI] 1.65-3.05, P < 0.001), and those with TB exhibited higher mortality (adjusted HR 1.59, 95% CI 1.41-1.79, P < 0.001). Old age (adjusted HR 2.40, 95% CI 1.92-2.99, P < 0.001), male sex (adjusted HR 2.13, 95% CI 1.76-2.57, P < 0.001), diabetes mellitus (adjusted HR 1.28, 95% CI 1.05-1.56, P = 0.013), and chronic obstructive pulmonary disease (COPD) (adjusted HR 1.44, 95% CI 1.19-1.75, P < 0.001) were identified as independent risk factors for TB in gastric cancer patients. Dyslipidemia was an independent protective factor for both TB (adjusted HR 2.13, 95% CI 1.73-2.62, P < 0.001) and mortality (adjusted HR 1.11, 95% CI 1.08-1.15, P < 0.001) in gastric cancer patients.Old age, male sex, diabetes mellitus, and COPD were independent risk factors for TB in gastric cancer. High-risk gastric cancer patients, especially those in TB-endemic areas, should be regularly screened for TB.

A Nation-Wide Cancer Registry-Based Study of Adenosquamous Carcinoma in Taiwan

BACKGROUND

Adenosquamous carcinoma (ASC) is a rare disease involving various organs, yet there are no large-scale population-based comparative studies on ASC among different organs.

METHODS

The incidence and overall survival of ASC among various organs in cases diagnosed in Taiwan from January 1, 2003 to December 31, 2010 were calculated and compared using data from the Taiwan Cancer Registry (TCR). The various organs were classified and divided into three different systems: the female reproductive, respiratory, and alimentary systems. Survival analysis were also compared among 30,850 patients diagnosed as ASC, adenocarcinoma (AC) or squamous cell carcinoma (SCC) in organs with frequent ASC.

RESULTS

During the study period, a total of 576 ASC cases were diagnosed in Taiwan. The most common primary system was respiratory (73.8%), followed by alimentary (16.2%) and female reproductive (10%). The overall survival were significantly higher for cases involving the female reproductive system, followed by the respiratory and alimentary systems (P = 0.016). The median overall survival were worse in males than females for cases involving the respiratory system (22.4 vs. 31.8 months, P = 0.044). Multivariate analysis showed that age ≧ 65, more advanced T and N categories were independent unfavorable prognostic factors of overall survival in ASC. ASC histology is an independent unfavorable prognostic factor compared with AC and SCC.

CONCLUSIONS

ASC at an old age and more advanced T and N categories were found to be associated with a poor prognosis.

Serum brain-derived neurotrophic factor levels and psychotic symptoms in heroin dependence

OBJECTIVES

Psychotic symptoms are commonly observed among heroin users. Low serum brain-derived neurotrophic factor (BDNF) levels have been reported in schizophrenia and psychosis; however, studies assessing the relationship between serum BDNF levels and psychotic symptoms in heroin dependence are lacking.

METHOD

A total of 31 heroin-dependent patients who had never experienced psychotic symptoms during heroin consumption and 21 patients with a history of psychotic symptoms were consecutively recruited. We measured by enzyme-linked immunosorbent assay (ELISA) serum BDNF levels during early abstinence. A gender- and age-matched sample of healthy controls was also recruited and underwent measurement of BDNF.

RESULTS

BDNF levels were significantly lower in patients with psychotic symptoms than in those without psychotic symptoms (P<0.001). BDNF levels were not found to be correlated with sex, age, age of onset, duration of heroin use, average daily dose of heroin use, frequency of heroin use, SDS scores, BAI scores and BDI scores in the psychotic subsamples (all P>0.05).

CONCLUSIONS

Our findings suggest that heroin-dependent patients with psychotic symptoms share some of the neurotrophic insult that characterizes schizophrenia and psychosis.

Bioinformatic Interrogation of 5p-arm and 3p-arm Specific miRNA Expression Using TCGA Datasets

MicroRNAs (miRNAs) play important roles in cellular functions and developmental processes. They are also implicated in oncogenesis mechanisms and could serve as potential cancer biomarkers. Using high-throughput miRNA sequencing information, expression of both the 5p-arm and 3p-arm mature miRNAs were demonstrated and generated from the single miRNA hairpin precursor. However, current miRNA annotations lack comprehensive 5p-arm/3p-arm feature annotations. Among known human mature miRNAs, only half of them are annotated with arm features. This generated ambiguous results in many miRNA-Sequencing (miRNA-Seq) studies. In this report, we have interrogated the TCGA (the Cancer Genome Atlas) miRNA expression datasets with an improved, fully annotated human 5p-arm and 3p-arm miRNA reference list. By utilizing this comprehensive miRNA arm-feature annotations, enhanced determinations and clear annotations were achieved for the miRNA isoforms (isomiRs) recognized from the sequencing reads. In the gastric cancer (STAD) dataset, as an example, 32 5p-arm/3p-arm OPEN ACCESS J. Clin. Med. 2015, 4 1799 specific miRNAs were found to be down-regulated and 24 5p-arm/3p-arm specific miRNAs were found to be up-regulated. We have further extended miRNA biomarker discoveries to additional TCGA miRNA-Seq datasets and provided extensive expression information on 5p-arm/3p-arm miRNAs across multiple cancer types. Our results identified several miRNAs that could be potential common biomarkers for human cancers.

The Risk Factors of Lymph Node Metastasis in Early Gastric Cancer

Endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) is an effective alternative treatment for early gastric cancer. However, a major concern is the likelihood of lymph node metastasis. From December 1987 to December 2006, 391 patients who underwent curative surgery for gastric cancer with mucosal (T1a, n = 265) or submucosal (T1b, n = 126) invasion and a retrieved lymph node number ≧ 15 were enrolled. The frequency and risk factors of lymph node metastasis were analyzed. The frequency of lymph node metastasis was 4.9 % in T1a lesions and 21.4 % in T1b lesions. Although the depth of submucosal tumor invasion was < 2 mm, there was a 28.6 % chance of lymph node metastasis. A T1b lesion, i.e., the width of the submucosal tumor invasion was < 5 mm, resulted in fewer lymph node metastases than lesions > 5 mm in width. Multivariate analysis demonstrated that Lauren's diffuse type and lymphatic invasion were independent risk factors for lymph node metastasis in T1a lesions, while lymphatic invasion was the strongest risk factor for lymph node metastasis in T1b lesions. EMR/ESD is a good alternative for T1a intestinal type adenocarcinoma without lymphatic invasion. Surgical resection is necessary for patients with T1b gastric cancer with lymphatic invasion.

Interrogation of microRNAs involved in gastric cancer using 5p-arm and 3p-arm annotated microRNAs

MicroRNAs are derived from endogenous stem-loop precursors, and play important roles in various biological processes. From next-generation sequencing data, it is suggested that both the 5p-arm and 3p-arm of mature miRNAs could be generated from a single miRNA hairpin precursor; however, the current miRNA databases fail to provide comprehensive arm annotation features, which could result in ambiguous and incomplete analyses. In the present report, we have annotated over 99.7% of miRNAs with the correct 5p-arm and 3p-arm features. The length distribution of all annotated miRNAs is around 22 nucleotides; however, the 5p-arm miRNAs seem to be longer than those of the 3p-arm, which is evident in the 23-nucleotide group. Our study effort generates comprehensive miRNA arm-feature annotation which can be utilized for better interrogation of miRNAs. In further analysis of human gastric cancer tissues, we identified 38 down-regulated miRNAs and 22 up-regulated arm-specific miRNAs using this new comprehensives miRNA list.

Adenosquamous carcinoma of the stomach and review of the literature

Adenosquamous carcinoma of the stomach is a very rare disease, consisting of less than 0.4 % of all stomach cancer. From 1991 to 2013, a total of 2800 patients received gastrectomy for gastric cancer at Taipei Veterans General hospital. Among them, seven patients (0.25 %) diagnosed as adenosquamous carcinoma were enrolled. The clinicopathologic characteristics and prognosis were analyzed. The mean age of the seven patients was 62.3 years-old. There were 5 males and 2 females. Six patients were stage III disease and one patient was stage IV disease. Four patients finally died of gastric cancer. Only one patient had no recurrence until death. Among the seven patients, adenocarcinoma component comprises the majority of the metastatic lymph node in 6 patients (85.7 %). The only one patient with major squamous cell carcinoma component in metastatic lymph node had no tumor recurrence till death. Adenosquamous carcinoma of stomach is a rare disease and is associated with a poor prognosis. The component of adenocarcinoma and squamous cell carcinoma in the metastatic lymph node may influence the prognosis.

Outcome after curative surgery for gastric cancer patients with type 2 diabetes

BACKGROUND

Bariatric surgery has been adapted to the management of morbid obesity, leading to not only loss of body weight but also improvement of type 2 diabetes mellitus (DM). The goal of our study was to evaluate the effect of gastrectomy in gastric cancer patients with type 2 DM.

METHODS

From 1989 to 2011, a total of 69 gastric cancer patients receiving curative surgery were enrolled in this study. They were diagnosed with type 2 DM preoperatively and all are alive without tumor recurrence. The clinical characteristics were compared between groups with improved or unimproved DM, and groups were also analyzed based on the extent of gastrectomy and different reconstruction methods.

RESULTS

Of the 69 patients, 58 received subtotal gastrectomy and 11 received total gastrectomy. The frequency of DM improvement was significantly higher after total gastrectomy than subtotal gastrectomy (81.8 vs. 36.2 %; p = 0.007). Patients with DM duration of less than 5 years tended to experience DM improvement after surgery more frequently than patients with DM duration of more than 5 years (p = 0.028). Roux-en-Y esophagojejunostomy (R-Ye) led to a higher rate of DM improvement than did R-Y gastrojejunostomy (R-Yg), especially in patients with DM duration more than 5 years. Among patients receiving duodenal bypass after gastrectomy, R-Ye was associated with a higher frequency of DM improvement than R-Yg and B-II.

CONCLUSIONS

The extent of gastrectomy rather than the reconstruction method played an important role in DM improvement after curative surgery for gastric cancer.

microRNA-221 and microRNA-18a identification in stool as potential biomarkers for the non-invasive diagnosis of colorectal carcinoma

BACKGROUND

The detection of microRNA (miRNA) dysregulation in stool is a novel approach for the diagnosis of colorectal carcinoma (CRC). The aim of this study is to investigate the use of miR-221 and miR-18a in stool samples as non-invasive biomarkers for CRC diagnosis.

METHODS

A miRNA expression array containing 667 miRNAs was performed to identify miRNA dysregulation in CRC tissues. We focused on miR-221 and miR-18a, two significantly upregulated miRNAs which were subsequently verified in 40 pairs of CRC tissues and 595 stool samples (198 CRCs, 199 polyps and 198 normal controls).

RESULTS

miR-221 and miR-18a were upregulated in the miRNA expression array. miR-221 and miR-18a levels were also significantly higher in 40 CRC tumours compared with their respective adjacent normal tissues. In stool samples, miR-221 and miR-18a showed a significant increasing trend from normal controls to late stages of CRC (P<0.0001). The levels of stool miR-221 and miR-18a were both significantly higher in subjects with stages I+II (miR-221: P<0.0001, miR-18a: P<0.0001) and stages III+IV of CRC (miR-221: P=0.0004, miR-18a: P<0.0001) compared with normal controls. The AUC of stool miR-221 and miR-18a were 0.73 and 0.67 for CRC patients as compared with normal controls, respectively. No significant differences in stool miR-221 and miR-18a levels were found between patients with proximal and distal CRCs. The use of antibiotics did not influence stool miRNA-221 and miRNA-18a levels.

CONCLUSIONS

Stool-based miR-221 can be used as a non-invasive biomarker for the detection of CRC.

Phylogenetic relationships among Octopodidae species in coastal waters of China inferred from two mitochondrial DNA gene sequences

Octopus in the family Octopodidae (Mollusca: Cephalopoda) has been generally recognized as a "catch-all" genus. The monophyly of octopus species in China's coastal waters has not yet been studied. In this paper, we inferred the phylogeny of 11 octopus species (family Octopodidae) in China's coastal waters using nucleotide sequences of two mitochondrial DNA genes: cytochrome c oxidase subunit I (COI) and 16S rRNA. Sequence analysis of both genes revealed that the 11 species of Octopodidae fell into four distinct groups, which were genetically distant from one another and exhibited identical phylogenetic resolution. The phylogenies indicated strongly that the genus Octopus in China's coastal waters is also not monophyletic, and it is therefore clear that the Octopodidae systematics in this area requires major revision. It is demonstrated that partial sequence information of both the mitochondrial genes 16S rRNA and COI could be used as diagnostic molecular markers in the identification and resolution of the taxonomic ambiguity of Octopodidae species.

Registry of gastric cancer treatment evaluation (REGATE): I baseline disease characteristics

AIMS

A better understanding of treatment patterns and outcomes in different countries should improve the management of patients with gastric cancer globally. The REgistry of GAstric Cancer Treatment Evaluation (REGATE) study was established to evaluate variations in gastric cancer disease characteristics and treatment patterns in different parts of the world.

METHODS

REGATE was a prospective international registry enrolling patients with newly diagnosed gastric cancer at any stage of the disease.

RESULTS

A total of 10 299 patients (65% male; mean age 59 years) were recruited in 22 countries between 2004 and 2008. Tumor location at a proximal site was more common in Europe, Latin America and North Africa (approximately 20%) than in Asia-Pacific, where antral location predominated. Signet-ring cell histology predominated except in Europe, where adenocarcinoma was most prevalent. Stage I cancers were more frequent in Asia-Pacific (39%) versus other regions (6-18%), whereas stage IV cancers were more frequent outside Asia-Pacific. Surgery was planned for most patients, although in general fewer patients actually received surgery than originally planned. Adjuvant therapy and palliative care were generally used more frequently than originally planned. Overall, 15% of patients received no treatment (Asia-Pacific 8%; Indian subcontinent 25%).

CONCLUSIONS

These results provide a comprehensive database representative of gastric cancer disease characteristics and treatment patterns across the world.

Impact of body mass index on postoperative outcome of advanced gastric cancer after curative surgery

INTRODUCTION

The impact of body mass index (BMI) on the outcome of advanced gastric cancer surgery is controversial. Between December 1987 and December 2006, a total of 947 advanced gastric cancer patients receiving curative resection with retrieved lymph node number >15 were studied and divided into three groups according to BMI (<25, 25-30, and >30 kg/m(2)).

RESULTS AND DISCUSSION

With regard to comorbidities present prior to surgery, higher BMI patients were more likely to have heart disease, type 2 diabetes, and hypertension than lower BMI patients. Compared with BMI <25 kg/m(2), higher BMI patients had longer operative time and more surgery-related morbidity. Multivariate Cox proportional-hazard analysis showed that age, pathological T and N categories, and lymphovascular invasion were independent prognostic factors. The initial recurrence patterns, 5-year overall survival, and cancer-specific survival were similar among the three groups.

CONCLUSION

Only in stage III gastric cancer with BMI less than 25 kg/m(2) patients receiving total gastrectomy had a more advanced pathological N category and a worse prognosis compared to those receiving subtotal gastrectomy. Higher BMI was associated with longer operative time and more surgery-related morbidity than lower BMI. BMI alone is not an independent prognostic factor.

Complete mitochondrial genome of Abramis brama orientalis Berg (cypriniformes, Cyprinidae, Leuciscinae)

In this study, we cloned and sequenced the complete mitochondrial genome of Abramis brama orientalis Berg. The genome was 16,610 bp (LR) in length and consisted of 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes and 2 main non-coding regions [the control region (CR) and the origin of the light strand replication], the gene composition and order of which was similar to those reported from other fish mitochondrial genomes. The overall base composition of the heavy strand was T 26.7%, C 26.5 %, A 30.0% and G 16.8%, with a slight A+T bias of 56.7%. This mitogenome sequence data would play an important role in population genetics and phylogenetic analysis of the Leuciscinae.

Microsatellite instability is associated with a better prognosis for gastric cancer patients after curative surgery

BACKGROUND

Microsatellite instability (MSI) is one of the leading mechanisms for the carcinogenesis of gastric cancer. Its prognostic value is controversial.

METHODS

Between May 1988 and Oct 2003, a total of 214 gastric cancer patients undergoing curative surgery were enrolled, and their MSI statuses were classified as MSI-H (high) or MSI-L/S (low/stable). The clinicopathologic characteristics of MSI-H and MSI-L/S gastric cancers were compared.

RESULTS

The MSI-H tumors accounted for 11.7 % (n = 25) of the 214 total gastric cancers. Although not statistically significant, the MSI-H gastric cancers were more frequently located in the lower third of the stomach (64 % vs. 49.2 %) and were more often the intestinal type (72 % vs. 61.4 %) compared to the MSI-L/S gastric cancers. The MSI-H gastric cancers had a significantly better 5-year overall survival (OS) rate (68 % vs. 47.6 %, p = 0.030) and a trend of a better 3-year disease-free survival rate (71.8 % vs. 55.2 %, p = 0.076) compared to the MSI-L/S gastric cancers. A multivariate analysis revealed that pathologic TNM stage and MSI status were the independent prognostic factors for OS after curative surgery.

CONCLUSIONS

Compared to MSI-L/S tumors, MSI-H tumors are associated with a better OS rate for gastric cancer patients after R0 resection.

microRNA-7 is a novel inhibitor of YY1 contributing to colorectal tumorigenesis

Using microRNA (miRNA) expression array, we identified that miR-7 was deregulated in colorectal cancer (CRC). We studied the biological role and molecular target of miR-7 in CRC. miR-7 was downregulated in six out of seven colon cancer cell lines. Ectopic expression of miR-7 suppressed colon cancer cell proliferation (P<0.05), induced apoptosis (P<0.05) and caused cell-cycle arrest in G1 phase (P<0.05). The tumor suppressive function of miR-7 was further confirmed in nude mice (P<0.05). The 3'-untranslated region (3'UTR) of Yin Yang 1 (YY1) mRNA contains an evolutionarily conserved miR-7 binding site using in silico searches, luciferase reporter assay and western blot analysis confirmed that miR-7 directly bound to YY1 3'UTR to negatively regulate the protein expression of YY1 in colon cancer cell lines HCT116 and LOVO. Intriguingly, knock-down of YY1 in three colon cancer cell lines (HCT116, LOVO and DLD1) consistently suppressed cell proliferation (P<0.01) and induced apoptosis (P<0.01), indicating the opposite functions of miR-7 and YY1 in CRC. Consistent with these data, ectopic expression of YY1 promoted cell growth by increasing proliferation (P<0.01) and suppressing apoptosis (P<0.001). The tumorigenic ability of YY1 was further confirmed in vivo in xenograft-nude mouse model (P<0.01). In addition, pathway analyses revealed that the oncogenic effect by YY1 was associated with inhibiting p53 and modulating its downstream effectors p15, caspase cascades and C-Jun, and activating Wnt signaling pathway through activating β-catenin, anti-apoptotic survivin and fibroblast growth factor 4. Furthermore, multivariate analysis revealed that patients with YY1 protein high expression had a significant decrease in overall survival, and Kaplan-Meier survival curves showed that these patients had significantly shorter survival than others (P<0.0001). In conclusion, MiR-7 is a novel miRNA with tumor suppressive function in colon cancer by targeting oncogenic YY1. YY1 promotes colon cancer growth through inhibiting p53 and promoting Wnt signaling pathways and serves as an independent prognostic biomarker for CRC patients.

Clinical practice guidelines for patients with gastrointestinal stromal tumor in Taiwan

For many years, the understanding of gastrointestinal stromal tumors (GISTs), which are the most common mesenchymal tumors of the gastrointestinal tract, has been very limited. However, it is now possible to provide a more precise definition through the use of pathology classification and molecular techniques. Coupled with the advancement of clinical practice, especially the development of targeted therapy, there is now a much better insight into its treatment. At present, organizations such as the National Comprehensive Cancer Network in the USA and the European Society for Medical Oncology in Europe have established a consensus and drawn up guidelines for the diagnosis, treatment, and follow-up of GISTs.With experts coming from various districts in Taiwan and combining the most recent clinical data and experiences, the Taiwan Surgical Society of Gastroenterology drafted the first national GIST treatment guidelines after a consensus meeting in 2007. Following subsequent advances in GIST diagnosis and treatment, further revisions and modifications have been made to the original guidelines. We present here the updated consensus and recommendations of the Taiwan Surgical Society of Gastroenterology for the diagnosis and treatment of GIST. We hope these guidelines can help enhance the quality of diagnosis, treatment, and care of patients with GIST in Taiwan.