Single port intra-gastric full thickness resection: Using "Rotation and Revolution Single Instrument Tie (RRSIT)".

BACKGROUND/AIMS: Recently, minimize incisions has led to a reduction in the number of ports, and has led to transumbilical single-port surgery. We evaluated the treatment result of single-port, intragastric, full thickness resections for gastric SMTs. In addition, we introduce a novel intracorporeal knot tying method. METHODOLOGY: From August 2010 to March 2011, five patients underwent single-port intragastric, full thickness gastric wedge resections. After performing a gastrostomy, a single port was inserted into the stomach. After full thickness resection, the defect in the gastric wall was sutured by full thickness interrupted suture and a new knot tying technique. RESULTS: The mean operative time was 129 ± 21.0 min and the mean mass size was 3.0±0.6 cm. There were two very low-risk GISTs, 2 leiomyomas, and 1 carcinoid. The post-operative course was uneventful in all patients. The mean hospital stay was 7.2±1.2 days. CONCLUSIONS: Single-port intra-gastric full thickness resection with novel intracorporeal knot tying method is feasible and safe. novel intracorporeal knot tying method is a very useful knot tying method. We expect the application of novel intracorporeal knot tying method to be diverse and broad.

Prognosis of Elderly Patients with Advanced Gastric Cancer without Serosal Invasion.

Introduction: The impact of age on the prognosis of patients with gastric cancer is controversial. This study aimed to investigate the clinicopathologic features and prognosis of elderly advanced gastric cancer patients without serosal invasion compared to their younger counterparts. Materials and Methods: We retrospectively evaluated 43 elderly patients with advanced gastric cancer without serosal invasion. The clinicopathologic findings were compared between the elderly (age >70 years) and young (age <36 years) patients. Results: Significantly higher numbers of elderly patients had tumours with differentiated histology, whereas more young patients had tumours with undifferentiated histology (P < 0.01). Curability (risk ratio, 3.122; confidence interval, 1.242-4.779; P < 0.001) was an independent prognostic factor of survival. The 5-year survival rates were not significantly different between the elderly and the young patients according to the absence of serosal invasion (80.0% vs. 77.9%; P = 0.654) and undergoing curative resection (82.0% vs. 78.9%; P = 0.312). Meanwhile, among the elderly patients, those who underwent curative resection had a better survival rate than those with non-curative resection (82.0% vs. 67.8%; P < 0.001). Conclusion: Elderly patients with advanced gastric cancer without serosal invasion do not have a worse prognosis than their younger counterparts, indicating that age does not impact the prognosis of advanced gastric cancer. The important prognostic factor was whether the patients underwent curative resection.

The Impact of Overweight and Obesity on Reduced-Port Laparoscopic Distal Gastrectomy for Gastric Cancer Patients: A Propensity Score Matching Analysis of a Single-Institution Data.

This study aimed to investigate the short-term postoperative outcomes of reduced-port laparoscopic distal gastrectomy and demonstrate its safety and feasibility in overweight and obese patients with gastric cancer. The medical records of 211 patients who underwent reduced-port laparoscopic distal gastrectomy, between August 2014 and April 2020, were reviewed. After propensity score matching, they were divided into a non-overweight group (n = 68) and overweight group (n = 68). Operative details and short-term surgical outcomes were compared between two groups. Reduced-port laparoscopic distal gastrectomy in overweight group showed statistically longer operation time (200.59 vs. 208.68 min, p = 0.044), higher estimated bleeding volume (40.96 vs. 58.01 mL, p = 0.001), and lesser number of harvested lymph nodes (36.81 vs. 32.13, p = 0.039). However, no significant differences were found in hospital course and other surgical outcomes. There was no mortality in either group, and the postoperative morbidity rate was not significantly different (14.7% vs. 16.2%). In the subgroup analysis, overweight and obesity did not significantly affect postoperative complication rates (16.2% vs. 16.2%, p = 1). We demonstrated comparable short-term surgical outcomes of reduced-port laparoscopic distal gastrectomy between the two groups (p = 0.412~1). Reduced-port laparoscopic distal gastrectomy was safe in overweight and obese patients with gastric cancer.

Elevated preoperative neutrophil to lymphocyte ratio predicts poor survival following resection in late stage gastric cancer.

BACKGROUND: Elevated neutrophil to lymphocyte ratio (N/L ratio) has been shown to be a prognostic indicator in various cancers. We aimed to investigate the prognostic significance of the preoperative N/L ratio in late stage gastric cancer. METHODS: From April 2004 to August 2007, 293 patients who had undergone gastrectomy with curative intent for the AJCC/UICC TNM Stage III or IV gastric cancer were included. N/L ratio was calculated from lymphocyte and neutrophil counts on routine blood tests taken prior to surgery. RESULTS: The median follow-up time for surviving patients was 38.2 months (4.2-65.5 months) and median preoperative N/L ratio was 2.06 (range 0.47-19.73). Subjects were dichotomized at the N/L value of 2.0. A multivariate analysis established a significant relationship between the N/L ratio and overall survival (HR=1.609; 95% confidence interval, CI, 1.144-2.264; P=0.006). The cutoff value up to 3.0, the value of 75 percentiles, showed a significant prognostic effect on disease-free survival (HR=1.654; 95% CI, 1.088-2.515; P=0.019). CONCLUSIONS: The results suggest that the elevated preoperative N/L ratio predicts poor disease-free and overall survival following resection for late stage gastric cancer. It may be utilized as a simple, reliable prognostic factor for risk stratification and will provide better treatment allocation.

Predisposing factors and management of postoperative bleeding after radical gastrectomy for gastric carcinoma.

PURPOSE: To promote proper management of postoperative bleeding, we investigated the clinical manifestations, predisposing factors, diagnostic approaches, and treatments of bleeding complications after gastric cancer surgery. METHODS: Using a prospectively constructed database, we reviewed retrospectively 39 patients who suffered bleeding complications from among a total 1027 patients who underwent surgery for gastric cancer between 2004 and 2008. RESULTS: Operating time (hazard ratio [HR] 1.842, 95% confidence interval [CI] 1.524-2.367) and body mass index (HR 1.454, 95% CI 1.128-1.792) were significant predisposing factors for postoperative bleeding after gastric cancer surgery. Luminal bleeding occurred in 16 patients: as simple anastomosis site bleeding, treated successfully with conservative or endoscopic treatment, in 13; and as pseudoaneurysmal bleeding in 3, treated successfully with surgery in 2, but resulting in the death of 1. Abdominal bleeding occurred in 23 patients, requiring surgery in 9 and arterial embolization in 1. The most common finding at reoperation was bleeding from the mesocolon surface. The mean hospital stay of patients with postoperative bleeding was 21 (± 20) days. CONCLUSIONS: Postoperative bleeding can be managed successfully with a tailored approach, considering its origins and clinical manifestations. Arterial pseudoaneurysms are a rare cause of luminal bleeding, but they can be fatal and should be suspected when extensive luminal bleeding presents after gastric cancer surgery.

Reduced-port laparoscopic distal gastrectomy in obese gastric cancer patients.

BACKGROUND: Reduced-port laparoscopic gastrectomy is currently widely performed for patients with gastric cancer. However, its safety in obese patients has not yet been verified. This is the first study on reduced-port laparoscopic distal gastrectomy (RpLDG) in obese patients with gastric cancer. This study aimed to evaluate the short-term surgical outcomes and investigate the feasibility and safety of RpLDG in obese patients with gastric carcinoma. MATERIAL AND METHODS: A total of 271 gastric cancer patients who underwent RpLDG at our institution were divided into two groups: non-obese [body mass index (BMI) <30 kg/m2, n = 251; NOG] and obese (BMI ≥30 kg/m2, n = 20; OG). The mean age of the enrolled patients was 64.8 ± 11.4 years, with 72.0% being men and 28.0% women. Operative details and short-term surgical outcomes, including hospital course and postoperative complications, were compared by retrospectively reviewing the medical records. RESULTS: No significant difference in operation time was found between the NOG and OG (205.9 ± 40.0 vs. 211.3 ± 37.3 minutes, P = 0.563). Other operative outcomes in the OG, including estimated blood loss (54.1 ± 86.1 vs. 54.0 ± 39.0 mL, P = 0.995) and retrieved lymph nodes (36.2 ± 16.4 vs. 35.5 ± 18.2, P = 0.875), were not inferior to those in the NOG. There were also no statistical differences in short-term surgical outcomes, including the incidence of surgical complications (13.9% vs. 10.0%, P = 1). CONCLUSION: RpLDG can be performed safely in obese gastric cancer patients by an experienced surgeon. It should be considered a feasible alternative to conventional port distal gastrectomy.

Transpyloric optic navigation of tumor using a laparoscope during totally laparoscopic distal gastrectomy for gastric cancer.

Purpose: The purpose of this study was to describe the technique of intraoperative transpyloric optic navigation (TPON) and determine its efficacy and feasibility during totally laparoscopic distal gastrectomy (TLDG) in patients with gastric cancer. Methods: Seventy-nine patients who underwent laparoscopic gastrectomy with transpyloric optic localization of the tumor from January 2016 through December 2018 were enrolled in this study. After resecting the first portion of the duodenum, the distal part of the stomach was exteriorized through an extended supraumbilical trocar site, and a balloon trocar was introduced from the pylorus to determine the location of tumor and determine its resection margin. The clinicopathologic and surgical outcomes were analyzed. Results: The tumor was located in the lower third of the stomach in 39 cases, the middle third in 34 cases, and the upper-third in six cases. Tumor localization was successful in 67 patients. The mean proximal margin was 41.7 ± 26.8 mm. There was no morbidity related to the technique. By the fifth postoperative day, the average white blood cell count was within the normal range and the average level of C-reactive protein showed a decreasing pattern. Conclusion: TPON of the tumor during TLDG is an effective and feasible method to determine the tumor location and to obtain an adequate resection margin.

CpG methylation of transcription factor 4 in gastric carcinoma.

BACKGROUND: Epigenetic silencing of tumor-related genes by CpG island methylation is an important mechanism for the development of many tumors, including gastric carcinoma. Deregulation of transcription factor 4 (TCF4) by promoter methylation was recently shown to play a key role in gastric carcinogenesis. METHODS: The extent of methylation in the TCF4 promoter was assessed using methylation-specific polymerase chain reaction (MSP) and pyrosequencing (PS) in 120 gastric carcinoma (GC) samples collected during gastrectomy, and in 40 normal gastric mucosa samples. RESULTS: The PS analysis of GCs revealed a higher frequency of TCF4 methylation (75.8%; 91/120). The methylation frequency for TCF4 by both MSP and PS techniques was significantly higher in advanced (75.0 and 91.7%, respectively) compared with early (60.0 and 60.0%, respectively, p < 0.05) GCs. There was a significant difference in TCF4 methylation between GCs and normal gastric mucosa (67.5 vs. 40.0%, respectively, by MSP and 75.8 vs. 30.0%, respectively, by PS; p < 0.05). There was significant correlation between TCF4 methylation status by PS and tumor size (p = 0.004), Lauren classification (p = 0.043), depth of invasion (p < 0.001), nodal metastasis (p = 0.021), and tumor-node-metastasis (TNM) stage (p = 0.045). CONCLUSIONS: These results suggest that inactivation of TCF4 by promoter methylation may play a role in the early stage of gastric carcinoma progression. Furthermore, standard polymerase chain reaction followed by PS may provide a more specific and quantitative diagnostic alternative to MSP, which may be of benefit in oncology research.

Aberrant methylation of DNA mismatch repair genes in elderly patients with sporadic gastric carcinoma: A comparison with younger patients.

BACKGROUND: Hypermethylation of promoters that regulate the expression of DNA repair genes is associated with gastric carcinoma (GC). Little is known regarding the association between age of disease onset and differences in molecular profiles. METHODS: The two study groups consisted of 100 elderly patients and 100 younger patients. The aberrant DNA methylation patterns of four mismatch repair genes, hMLH1, hMSH2, hMSH3, and MGMT, were compared by bisulfite modification and methylation-specific PCR (MSP). RESULTS: The methylation frequencies for hMLH1 and hMSH3 were significantly higher for the elderly than for the younger GC patients (P < 0.001 and P = 0.031, respectively). A significant correlation was observed between aberrant hMLH1, hMSH3, and MGMT methylation and the loss of hMLH1, hMSH3, and MGMT protein expression (P < 0.001, P = 0.002, and P = 0.001, respectively). The prevalence of aberrant hMLH1 and hMSH3 methylation increased significantly with age. CONCLUSION: These results suggest that the methylation of hMLH1 and hMSH3 is age related and thus may play an important role in gastric carcinogenesis in the elderly. Screening for hMLH1 and hMSH3 methylation may have clinical significance for the evaluation of elderly patients with GC.

Clinicopathologic features of gastric carcinoma patients who undergo a total gastrectomy.

Epidemiologic studies show a continued increase in the number of total gastrectomies (TGs) performed. We compared the clinicopathologic features and outcomes of patients who underwent a TG to those who received a distal gastrectomy (DG). Cases of 696 patients treated with TG were reviewed retrospectively. Multivariate analysis showed that age, tumor size, presence of serosal invasion, lymph node metastasis, and curability were significant prognostic factors for survival of patients who had a TG. The 5-year survival rate of patients who underwent a TG (39.5%) was lower than that of those receiving a DG (56.1%; P < 0.001). Patients who underwent a TG had a poor prognosis, which was mainly due to its more-advanced stage compared to that of patients who received a DG. Early detection is important for improving the prognosis.

Lack of death receptor 4 (DR4) expression through gene promoter methylation in gastric carcinoma.

BACKGROUND AND AIMS: To determine the underlying mechanism for the differential expression, the extent of promoter methylation in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-related genes acting downstream of TRAIL was examined in early and advanced gastric carcinomas. METHODS: The extent of promoter methylation in the DR4, DR5, DcR1, DcR2, and CASP8 genes was quantified using bisulfite modification and methylation-specific polymerase chain reaction. RESULTS: The promoters for DcR1, DcR2, and CASP8 were largely unmethylated in early gastric carcinoma, advanced gastric carcinoma, and controls, with no significant difference among them. Protein levels of DR4, DcR1, and DcR2 as revealed by immunohistochemistry correlated with the extent of the respective promoter methylation (P < 0.05 in all cases). Hypomethylation, rather than hypermethylation, of the DR4 promoter was noted in invasive gastric malignancies, with statistical significance (P = 0.003). CONCLUSION: The promoter methylation status of TRAIL receptors in gastric carcinoma may have clinical implications for improving therapeutic strategies in patients with gastric carcinoma.

Genetic alterations of Wnt signaling pathway-associated genes in hepatocellular carcinoma.

BACKGROUND AND AIM: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Recently, abnormal activation of the Wnt pathway has been found to be involved in the carcinogenesis of HCC. However, the relationship between genetic changes in the Wnt pathway-associated genes and its protein expression has not been studied in patients with HCC and cirrhotic nodules. The purpose of this study is to explore the contribution of inappropriate activation of the Wnt pathway in liver carcinogenesis. METHODS: Somatic mutation in exons 3-5 of AXIN1 and exon 3 of beta-catenin were analyzed by direct sequencing and expression of axin and beta-catenin proteins by immunohistochemistry in a series of 36 patients with HCC and cirrhosis. RESULTS: The AXIN1 and beta-catenin gene mutations were observed in 25% (9/36) and 2.8% (1/36) of HCCs, respectively. All mutations detected in AXIN1 and beta-catenin genes were missense point mutations. Abnormal nuclear expression of beta-catenin was observed in 11 of 36 cases of HCCs (30.6%), but not in cirrhotic nodules. Reduced or absent expression of axin was seen in 24 of 36 HCCs (66.7%). The abnormal expression of beta-catenin and axin proteins was closely correlated with mutations of AXIN1 and beta-catenin (P < 0.0001 and P = 0.008, respectively). CONCLUSIONS: These data suggest that mutation of AXIN1 gene is a frequent and late event for HCC associated with cirrhosis, and is correlated significantly with abnormal expression of axin and beta-catenin. Therefore, activation of Wnt signaling through AXIN1 rather than beta-catenin mutation might play an important role in liver carcinogenesis.

Prognosis of upper-third gastric carcinoma patients with invasion of the lower esophagus.

BACKGROUND AND AIMS: Epidemiological studies show a continuing rise in the prevalence of upper-third gastric carcinoma. We compared the clinicopathologic features and prognosis in these patients, with and without lower esophageal invasion. PATIENTS AND METHODS: We reviewed the hospital records of 42 patients with lower esophageal invasion seen between 1986 and 2000. RESULTS: Borrmann type IV gastric carcinoma was more frequently found in patients with esophageal invasion (P < 0.001). Multivariate analysis indicated that curability, the extent of lymph node dissection, and lymph node metastases were significant prognostic factors. When the patients with esophageal invasion were divided into those with or without curative resection, the 5-year survival rates were 37.3% and 0%, respectively (P < 0.001). In patients with lymph node dissection above the D2 lymph node, the 5-year survival rate was higher than that of patients with dissection below the D2 node level (34.4% vs 0%, P < 0.001). CONCLUSION: According to our results, curative resection and extensive lymph node dissection were the determining factors in improving survival.

Is palliative resection necessary for gastric carcinoma patients?

BACKGROUND AND AIMS: The benefit of palliative resection for gastric carcinoma patients remains controversial. We thus evaluated the survival benefit of palliative resection in advanced gastric carcinoma patients. MATERIALS AND METHODS: We reviewed the hospital records of 466 gastric carcinoma patients who had palliative resection and compared the clinicopathologic findings to those of patients who underwent a bypass or exploration from 1986 to 2000. RESULTS: Cox's proportional hazard regression model revealed only one independent statistically significant prognostic parameter, the presence of peritoneal dissemination (risk ratio, 0.739; 95% confidence interval, 0.564-0.967; P < 0.05). The 5-year survival rate of patients who had palliative resection was higher than that of patients who did not (7.03 vs 0%, P < 0.001). When the 5-year survival rates of patients with peritoneal dissemination were examined, the rate was higher for those who underwent resection (4.43 vs 0%, P < 0.001). CONCLUSION: The results highlight the improved survivorship of gastric carcinoma patients with palliative resection compared to those who did not undergo the procedure. Although curative resection is not possible in this group of patients, we recommend performing resection aimed at palliation.

Prognosis of gastric carcinoma invading the mesocolon.

OBJECTIVE: The prognosis is poor when gastric carcinoma invades adjacent organs. We evaluated the outcome indicators in gastric carcinoma patients with mesocolon invasion. METHODS: We reviewed the hospital records of 169 gastric carcinoma patients with mesocolon invasion seen between 1986 and 2000 at Chonnam National University Hospital. RESULTS: The curative resection rate in gastric carcinoma patients with mesocolon invasion was 29.6% (50/169). Using Cox's proportional hazards regression model, curability was the only independent, statistically significant prognostic parameter (risk ratio, 1.48; 95% confidence interval, 0.902.46; p < 0.05). The 5-year survival rate was higher for patients who underwent curative resection (15.5%) than for those who underwent non-curative resection (2.6%; p < 0.001). The 5-year survival rate was higher for patients who underwent resection (7.3%) than for those who did not (bypass and exploration groups, 5.1% and 0%, respectively; p < 0.001). CONCLUSION: The results showed improved survival of gastric carcinoma patients with mesocolon invasion who underwent curative resection compared to those who did not. Improving the prognosis for patients with mesocolon invasion requires curative resection.

Transition from Conventional to Reduced-Port Laparoscopic Gastrectomy to Treat Gastric Carcinoma: a Single Surgeon's Experience from a Small-Volume Center.

PURPOSE: This study aimed to evaluate the surgical outcomes and investigate the feasibility of reduced-port laparoscopic gastrectomy using learning curve analysis in a small-volume center. MATERIALS AND METHODS: We reviewed 269 patients who underwent laparoscopic distal gastrectomy (LDG) for gastric carcinoma between 2012 and 2017. Among them, 159 patients underwent reduced-port laparoscopic gastrectomy. The cumulative sum technique was used for quantitative assessment of the learning curve. RESULTS: There were no statistically significant differences in the baseline characteristics of patients who underwent conventional and reduced-port LDG, and the operative time did not significantly differ between the groups. However, the amount of intraoperative bleeding was significantly lower in the reduced-port laparoscopic gastrectomy group (56.3 vs. 48.2 mL; P<0.001). There were no significant differences between the groups in terms of the first flatus time or length of hospital stay. Neither the incidence nor the severity of the complications significantly differed between the groups. The slope of the cumulative sum curve indicates the trend of learning performance. After 33 operations, the slope gently stabilized, which was regarded as the breakpoint of the learning curve. CONCLUSIONS: The surgical outcomes of reduced-port laparoscopic gastrectomy were comparable to those of conventional laparoscopic gastrectomy, suggesting that transition from conventional to reduced-port laparoscopic gastrectomy is feasible and safe, with a relatively short learning curve, in a small-volume center.

The Benefits of Resection for Gastric Carcinoma Patients with Non-curative Factors.

The benefits of resection for gastric carcinoma patients with non-curative factors remain controversial. Thus, we evaluated the survival benefits of resection in these gastric carcinoma patients. We reviewed the hospital records of 467 gastric carcinoma patients with non-curative factors who had resection (n=305) and compared their clinicopathological findings with individuals (n=162) who underwent bypass or exploration from 1996 to 2010. The 3-year survival rate of patients who had resection was higher than was that of patients who did not (13.2 vs. 7.2%, respectively p<0.001). Cox's proportional hazard regression analysis revealed that only one factor was an independent, statistically significant prognostic parameter: the presence of peritoneal dissemination (risk ratio, 1.37; 95% confidence interval, 1.04-1.79; p<0.05). The 3-year survival rate of patients with peritoneal dissemination was higher in individuals who underwent resection compared with those who did not (9.5 vs. 4.7%, respectively; p<0.001). The current results highlight the improved survival rates of gastric carcinoma patients with non-curative factors who underwent surgery compared with those who did not. Although resection is not curative in this group of patients, we still recommend performing the procedure.

Surgical Outcomes of Laparoscopic Resection for Subepithelial Lesions on the Gastric Fundus Performed in the Supine or Lateral Decubitus Position.

BACKGROUND: Laparoscopic resection of gastric subepithelial lesions (SELs) located on the posterior wall of the gastric fundus is technically difficult and time-consuming. To facilitate access, we propose performing the laparoscopic procedure with patients in a right lateral decubitus position, rather than the standard supine position. The aim of our study was to compare operative and clinical outcomes for laparoscopic SEL resection performed in either the right lateral decubitus or the traditional supine position. METHODS: The analysis was based on the data of 62 patients who underwent laparoscopic resection of SELs of the gastric fundus at Chonnam National University Hospital: 30 patients in the supine position (SUP) group and 32 in the right lateral decubitus position (RLD) group. All surgeries were performed by a single surgeon. Between-group comparisons were evaluated by Student's t, chi-squared, or Fisher's least squared tests, as appropriate for the data set. RESULTS: Compared with the SUP group, the RLD had shorter operative time (103 minutes versus 52 minutes, P < .001), less intraoperative blood loss (71 mL versus 31 mL, P < .001), and lower C-reactive protein levels on postoperative days 1 and 2 (P < .005). Time to first flatus and length of hospital stay were comparable between groups. CONCLUSION: Laparoscopic gastric wedge resection for SELs on the gastric fundus in the right lateral decubitus position is feasible and safe, and provides operative advantages over the supine position.

Quantitative analysis of COX-2 promoter methylation in gastric carcinoma.

PURPOSE: To determine the occurrence of COX-2 methylation in gastric carcinoma (GC), the status and level of CpG methylation in the promoter region of cyclooxygenase-2 (COX-2) were analyzed in early and advanced GCs, as well as in normal gastric tissues. METHODS: The extent of promoter methylation of the COX-2 gene was assessed quantitatively using pyrosequencing in 60 early and 60 advanced GCs samples harvested upon gastrectomy, and 40 normal gastric mucosa samples from patients with benign gastric diseases as controls. RESULTS: The methylation frequency for the COX-2 gene was significantly higher in early than in advanced GCs (40.0% vs. 20.0%, P < 0.05). A significant difference was found in COX-2 methylation between GCs and normal gastric tissues (30.0% vs. 10.0%, by PS; P < 0.05). COX-2 gene methylation was significantly associated with the depth of invasion (P = 0.003), lymph node metastasis (P = 0.009), distant metastasis (P = 0.036), and TNM staging (P = 0.007). The overall survival of patients with COX-2 methylation was significantly lower than that of patients without COX-2 methylation (P = 0.005). CONCLUSION: These results demonstrated that COX-2 promoter methylation was significantly higher in tumor tissues, and was an early event for GC, thus, COX-2 gene methylation may be important in the initial development of gastric carcinogenesis. Thus, GCs with methylation in COX-2 may not be good candidates for treatment with COX-2 inhibitors. Furthermore, COX-2 methylation could be a significant prognostic factor predicting a favorable effect on GC patient outcome when downregulated.

Hyaluronic Acid-Based Nanomaterials for Cancer Therapy.

Hyaluronic acid (HA) is a nonsulfated glycosaminoglycan and a major component of the extracellular matrix. HA is overexpressed by numerous tumor cells, especially tumor-initiating cells. HA-based nanomaterials play in importance role in drug delivery systems. HA is used in various types of nanomaterials including micelle, polymersome, hydrogel, and inorganic nanoparticle formulations. Many experiments show that HA-based nanomaterials can serve as a platform for targeted chemotherapy, gene therapy, immunotherapy, and combination therapy with good potential for future biomedical applications in cancer treatment.