Comparison of totally laparoscopic total gastrectomy using an endoscopic linear stapler with laparoscopic-assisted total gastrectomy using a circular stapler in patients with gastric cancer: A single-center experience

AIM

To evaluate the safety and efficacy of totally laparoscopic total gastrectomy (TLTG) with esophagojejunostomy using a linear stapler compared with laparoscopic-assisted total gastrectomy (LATG) using a circular stapler in gastric cancer patients.

METHODS

We retrospectively reviewed 687 patients who underwent laparoscopic total gastrectomy for gastric cancer at a single institution from August 2008 to August 2014. The patients were divided into two groups according to the type of operation: 421 patients underwent TLTG and 266 underwent LATG. Clinicopathologic characteristics and surgical outcomes in the two groups were compared and analyzed.

RESULTS

The TLTG group had higher mean ages at the time of operation (57.78 ± 11.20 years and 55.69 ± 11.96 years, P = 0.020) and more histories of abdominal surgery (20.2% and 12.4%, P = 0.008) compared with the LATG group. Surgical outcomes such as intraoperative and postoperative transfusions, combined operations, pain scores and administration of analgesics, and complications were similar between the two groups. However, compared with the LATG group, the TLTG group required a shorter operation time (149 min vs 170 min, P < 0.001), had lower postoperative hematocrit change (3.49% vs 4.04%, P = 0.002), less intraoperative events (3.1% vs 10.2%, P < 0.001), less intraoperative anastomosis events (2.4% vs 7.1%, P = 0.003), faster postoperative recovery such as median time to first flatus (3.30 d vs 3.60 d, P < 0.001), faster median commencement of soft diet (4.30 d vs 4.60 d, P < 0.001) and shorter length of postoperative hospital stay (6.75 d vs 7.02 d, P = 0.005).

CONCLUSION

The intracorporeal method for reconstruction of esophagojejunostomy using a linear stapler may be considered a feasible procedure comparing with extracorporeal anastomosis using circular stapler because TLTG is simpler and more straightforward than LATG. Therefore, TLTG can be recommended as an appropriate procedure for gastric cancer.

Generation of interspecies limited chimeric nephrons using a conditional nephron progenitor cell replacement system

Animal fetuses and embryos may have applications in the generation of human organs. Progenitor cells may be an appropriate cell source for regenerative organs because of their safety and availability. However, regenerative organs derived from exogenous lineage progenitors in developing animal fetuses have not yet been obtained. Here, we established a combination system through which donor cells could be precisely injected into the nephrogenic zone and native nephron progenitor cells (NPCs) could be eliminated in a time- and tissue-specific manner. We successfully achieved removal of Six2+ NPCs within the nephrogenic niche and complete replacement of transplanted NPCs with donor cells. These NPCs developed into mature glomeruli and renal tubules, and blood flow was observed following transplantation in vivo. Furthermore, this artificial nephron could be obtained using NPCs from different species. Thus, this technique enables in vivo differentiation from progenitor cells into nephrons, providing insights into nephrogenesis and organ regeneration.

The transplantation of tissue-specific progenitor cells may be an approach in organ regeneration. Here the authors show that the nephron progenitor population of a developing mouse kidney, when ablated, can be replaced by exogenously supplied rat nephron progenitors, generating interspecies nephrons.

Phase I/II study of a combination of capecitabine, cisplatin, and intraperitoneal docetaxel (XP ID) in advanced gastric cancer patients with peritoneal metastasis

BACKGROUND

This study was conducted to determine the recommended dose (RD) of intraperitoneal docetaxel (ID) in combination with systemic capecitabine and cisplatin (XP) and to evaluate its efficacy and safety at the RD in advanced gastric cancer (AGC) patients with peritoneal metastasis.

METHODS

AGC patients with peritoneal metastasis received XP ID, which consists of 937.5 mg/m² of capecitabine twice daily on days 1-14, 60 mg/m² of intravenous cisplatin on day 1, and intraperitoneal docetaxel at 3 different dose levels (60, 80, or 100 mg/m²) on day 1, every 3 weeks. In the phase I study, the standard 3 + 3 method was used to determine the RD of XP ID. In the phase II study, patients received RD of XP ID.

RESULTS

In the phase I study, ID 100 mg/m² was chosen as the RD, with one dose-limiting toxicity (ileus) out of six patients. The 39 AGC patients enrolled in the phase II study received the RD of XP ID. The median progression-free survival was 11.0 months (95% CI 6.9-15.1), and median overall survival was 15.1 months (95% CI 9.1-21.1). The most frequent grade 3/4 adverse events were neutropenia (38.6%) and abdominal pain (30.8%). The incidence of abdominal pain cumulatively increased in the later treatment cycles.

CONCLUSIONS

Our study indicated that XP ID was effective, with manageable toxicities, in AGC patients with peritoneal metastasis. As the cumulative incidence of abdominal pain was probably related to bowel irritation by ID, it might be necessary to modify the dose.

Verteporfin inhibits gastric cancer cell growth by suppressing adhesion molecule FAT1

Gastric cancer (GC) is a leading cause of death worldwide and in urgent need of targeted drug development. In the current, we investigated the ability of a repositioned drug verteporfin (VP), originally a treatment for macular degeneration, to inhibit GC cell growth. VP inhibited growth of various GC cell lines. Gene expression profiling of GC cell lines treated with VP revealed that migration-related genes and those with oncogenic potential were down-regulated. Of these genes, we found that FAT1, an adhesion molecule promoting cell invasion, was highly suppressed by VP. Silencing of FAT1 suppressed cell migration and invasion as VP did. FAT1 expression was up-regulated in tumors, and patients with high FAT1-expressing tumors had a worse prognosis. We propose that VP- targeting FAT1 to suppress metastatic potential is a promising therapeutic strategy against GC.

VUV spectroscopy in impurity injection experiments at KSTAR using prototype ITER VUV spectrometer

The ITER vacuum ultra-violet (VUV) core survey spectrometer has been designed as a 5-channel spectral system so that the high spectral resolving power of 200-500 could be achieved in the wavelength range of 2.4-160 nm. To verify the design of the ITER VUV core survey spectrometer, a two-channel prototype spectrometer was developed. As a subsequent step of the prototype test, the prototype VUV spectrometer has been operated at KSTAR since the 2012 experimental campaign. From impurity injection experiments in the years 2015 and 2016, strong emission lines, such as Kr xxv 15.8 nm, Kr xxvi 17.9 nm, Ne vii 46.5 nm, Ne vi 40.2 nm, and an array of largely unresolved tungsten lines (14-32 nm) could be measured successfully, showing the typical photon number of 10¹³-10¹⁵ photons/cm² s.

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

Background/Aims

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

Methods

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

Results

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

Conclusions

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

Highly Porous Polymer Matrices as a Three-Dimensional Culture System for Hepatocytes

Hepatocyte-based therapies (e.g., hepatocyte transplantation and extracorporeal support devices) may provide alternative therapies to treat patients with liver disease, but suitable approaches to localize these cells to a given location while maintaining liver-specific gene expression must be developed. The suitability of highly porous three-dimensional sponges fabricated from poly (l-lactic acid) [PLLA] as an hepatocyte culture system was evaluated in this study. Sponges were fabricated utilizing a particulate leaching technique, and were approximately 95% porous, with an average pore diameter of 180 μm. Hepatocytes seeded into these sponges adhered and remained viable for 14 days. However, the secretion rate of albumin from these cells, an indication of liver-specific gene expression, was low (approximately 6 pg/cell/day at day 1), and decreased steadily over the 14 days of the experiment. Coating sponges with collagen, and more preferably, immobilizing cells within the PLLA sponges with a collagen gel, led to enhanced cell survival and albumin secretion at all time points. These data suggest that porous PLLA sponges may provide a novel system for long-term culture of hepatocytes, and proper design of the system may allow the liver-specific gene expression of hepatocytes transplanted in these matrices to be enhanced.

Reduction of Slit Diaphragm-associated Molecules by Sirolimus: Is it Enough to Induce Proteinuria?

Sirolimus (SRL), a mammalian target of rapamycin inhibitor, is widely used in transplantation, but the mechanisms whereby it induces adverse effects, such as proteinuria and edema, remain unclear. To determine whether isolated SRL induces proteinuria or not, the authors intraperitoneally injected C57BL/6 mice with different doses of SRL (0 mg/[kg·d], 3 mg/[kg·d], 10 mg/[kg·d], or 30 mg/[kg·d]) for 24 days. Urinary albumin excretion was then quantified using a double-sandwich enzyme-linked immunosorbent assay, and serum creatinine levels were measured using a single dry-film chemistry auto-analyzer. The mRNA expression levels of various genes were also measured by polymerase chain reaction. Urinary albumin was not detected in the SRL-treated mice, but serum creatinine levels were found to increase dose-dependently and were significantly higher in the animals treated with 30 mg/kg of SRL than in untreated controls. Glomerular mRNA expression profiling showed down-regulations of podocyte-related genes (Wilms tumor 1, synaptopodin, nephrin, CD2-associated protein, and podocin) and of transforming growth factor-beta (a marker of fibrosis) in sirolimus-treated mice. In addition, expressions of the antiapoptotic genes Bcl-2 and Bcl-xL were also down-regulated. Furthermore, the protein levels of these genes in mice kidney were also decreased by sirolimus. Although sirolimus treatment reduced the expressions of slit diaphragm-associated molecules and increased serum creatinine levels, it failed to induce proteinuria. Our findings indicate that proteinuria is not induced by isolated SRL treatment. Further studies are required to identify conditions in which sirolimus induces proteinuria.

Phase II Study of Induction Chemotherapy with Docetaxel, Capecitabine, and Cisplatin Plus Bevacizumab for Initially Unresectable Gastric Cancer with Invasion of Adjacent Organs or Paraaortic Lymph Node Metastasis

Purpose

The purpose of this study was to evaluate the efficacy and safety of induction chemotherapy with docetaxel, capecitabine, and cisplatin (DXP) plus bevacizumab (BEV) on initially unresectable locally advanced gastric cancer (LAGC) or paraaortic lymph node (PAN) metastatic gastric cancer (GC).

Materials and Methods

Patients with LAGC or unresectable PAN metastatic GC received six induction chemotherapy cycles (60 mg/m² docetaxel intravenously on day 1, 937.5 mg/m² capecitabine orally twice daily on days 1-14, 60 mg/m² cisplatin intravenously on day 1, and 7.5 mg/kg BEV intravenously on day 1 every 3 weeks), followed by conversion surgery. The primary endpoint was R0 resection rate.

Results

Thirty-one patients with invasion to adjacent organs but without PAN metastasis (n=14, LAGC group) or with PAN metastasis regardless of invasion (n=17, PAN group) were enrolled between July 2010 and December 2014. Twenty-seven patients (87.1%) completed six chemotherapy cycles. The most common grade ≥ 3 toxicities were neutropenia (71%), neutropenia with fever/infection (22.6%/3.2%), and stomatitis (16.1%). The clinical response and R0 resection rates were 64.3% (95% confidence interval [CI], 46.6 to 82.0) and 64.5% (LAGC group, 71.4%; PAN group, 58.8%), respectively. The pathological complete regression rate was 12.9%. After a median follow-up of 44.5 months (range, 39.4 to 49.7 months), the median progression-free survival and overall survival were 13.1 months (95% CI, 8.9 to 17.3) and 38.6 months (95% CI, 22.0 to 55.1), respectively.

Conclusion

Induction chemotherapy with DXP+BEV displayed antitumor activities with encouraging R0 resection rate and manageable toxicity profiles on patients with LAGC or PAN metastatic GC.

Comparison of long-term outcomes of endoscopic submucosal dissection and surgery for esophagogastric junction adenocarcinoma

BACKGROUND

Endoscopic submucosal dissection (ESD) has become accepted as the standard treatment for early gastric cancer. However, comparative outcomes of ESD and surgery have not been evaluated for adenocarcinoma in the esophagogastric junction (EGJ). We investigated the long-term outcomes of ESD compared with those of surgery for adenocarcinoma in the EGJ.

METHODS

Patients who underwent ESD or surgery for Siewert type II adenocarcinoma between 2005 and 2010 and who met the absolute and expanded criteria for endoscopic resection were eligible. Clinical features and treatment outcomes were retrospectively reviewed using medical records.

RESULTS

Of the 79 patients included, 40 underwent ESD and 39 underwent surgery. During the median follow-up period of 60.9 months (range, 13.1-125.4 months), the 5-year overall survival rates were 93.9% and 97.3% for the ESD and surgery groups, respectively (p = 0.376). There were no gastric cancer-related deaths in either group. Adverse events occurred in 11 patients (13.9%) overall, and the incidence of treatment-related adverse events was similar between the two groups (10.0% vs. 17.9%, p = 0.308).

CONCLUSIONS

ESD may be an effective alternative to surgery for the treatment of early gastric cancer in the EGJ based on the comparable long-term outcomes.

Comparison of long-term outcomes of endoscopic submucosal dissection and surgery for esophagogastric junction adenocarcinoma

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Background: Endoscopic submucosal dissection (ESD) has been accepted as standard treatment for early gastric cancer. However, comparative outcomes of ESD and surgery have not been evaluated for adenocarcinoma in the esophagogastric junction (EGJ). We investigated the long-term outcomes of ESD compared with surgery for adenocarcinoma in the EGJ. Methods: Subjects who underwent ESD or surgery for Siewert type II adenocarcinoma which met absolute and expanded criteria between 2005 and 2010 were eligible for this study. Clinical features and treatment outcomes were retrospectively reviewed using medical records. Results: Among 79 patients included, 40 underwent ESD and 39 underwent surgery. During the median follow-up period of 60.9 months (range: 13.1-125.4 months), the 5-year overall survival rates were 93.9% and 97.3% for ESD and surgery groups, respectively ( p= 0.376). There was no gastric cancer-related deaths in either groups. Adverse events occurred in 11 patients (13.9%) overall and the incidence of treatment-related adverse events was similar between two groups (10.0% vs. 17.9%, p= 0.308). Conclusions: ESD may be an effective alternative to surgery for the treatment of early gastric cancer in the EGJ, based on comparable long-term outcomes.

Associations between CYP2A6 polymorphisms and outcomes of adjuvant S-1 chemotherapy in patients with curatively resected gastric cancer

BACKGROUND

Oral fluoropyrimidine S-1 contains tegafur, which is metabolized to 5-fluorouracil by cytochrome P450 2A6 (CYP2A6). We here examined associations between CYP2A6 polymorphisms and treatment outcomes of adjuvant S-1 in gastric cancer patients.

METHODS

Patients received adjuvant S-1 (40 mg/m² twice daily, days 1-28, every 6 weeks for eight cycles) after curative surgery for pathological stage II-III gastric cancer. We analyzed the wild-type allele (W) (CYP2A6*1) and four variant alleles (V) (CYP2A6*4, *7, *9, *10) that abolish or reduce this enzyme activity.

RESULTS

Patients (n = 200) were enrolled between November 2007 and July 2013 with the following clinical characteristics: median age, 57 years (range, 32-83 years); 128 men, 72 women. With a median follow-up of 46.4 months, the 3-year relapse-free survival (RFS) and overall survival (OS) rates were 83.1 % (95 % CI, 77.7-88.5 %) and 94.8 % (95 % CI, 91.6-98.0 %), respectively. Genotype distributions were as follows: W/W (n = 49, 24.5 %), W/V (n = 94, 47.0 %), and V/V (n = 57, 28.5 %). Overall toxicity did not differ according to genotype for any grade (p = 0.612) or grade ≥3 (p = 0.143). However, RFS differed significantly according to CYP2A6 genotype. The 3-year RFS rates were 95.9 % for W/W, 83.1 % for W/V, and 72.5 % for V/V (p = 0.032). Carriers of W/V and V/V genotypes had a poorer RFS with a hazard ratio of 3.41 (95 % CI, 1.01-11.52; p = 0.049) and 4.03 (95 % CI, 1.16-13.93; p = 0.028), respectively, compared with the W/W genotype.

CONCLUSIONS

CYP2A6 polymorphisms are not associated with toxicity of S-1 chemotherapy, but correlate with the efficacy of S-1 in the adjuvant setting for gastric cancer.

Comparison the sixth and seventh editions of the AJCC staging system for T1 gastric cancer: a long-term follow-up study of 2124 patients

BACKGROUND/AIM

The aim of this study was to establish an appropriate TNM staging system for early gastric cancer.

METHODOLOGY

We evaluated 2124 patients who had undergone gastrectomy for early gastric cancer between 1989 and 2001.

RESULTS

Using the seventh edition of the American Joint Committee on Cancer (AJCC) staging system, we found no significant differences in tumor recurrence and survival between N1 and N2 cancers or between N3a and N3b cancers, whereas the survival curves for N2 and N3 cancers were quite different. Similarly, using the classification in the sixth edition of the AJCC staging system, we found no significant difference in survival between the N2 and N3 cancer groups, whereas the survival curves for N1 versus N2 or N3 cancers were quite different.

CONCLUSIONS

The classifications in the sixth and seventh editions of the AJCC staging system have a limitation for T1 gastric cancer (early gastric cancer).

Remote Preconditioning on Rat Hepatic Ischemia-Reperfusion Injury Downregulated Bax and Cleaved Caspase-3 Expression

OBJECTIVE

Hepatic ischemia-reperfusion injury (IRI) is considered a major cause of hepatic damage in liver surgery. The aim of this study was to investigate the effect of the remote ischemic perconditioning method on hepatic IRI in a rat model.

METHODS

Seventeen rats underwent hepatic IRI for 30 minutes followed by reperfusion, and were divided into 3 groups: group I, only hepatic IRI (n = 5); group II, hepatic IRI with remote perconditioning (n = 7); and group III, hepatic IRI with remote postconditioning (n = 5).

RESULTS

For Bax/β-actin, mean values of the 3 groups (±standard deviation) were 1.29 ± 0.26 (group I), 0.89 ± 0.15 (group II), and 1.02 ± 0.23 (group III). The level of Bax/β-actin in group II was significantly lower than in group I (P < .01). The cleaved Caspase-3/β-actin ratio for groups I, II, and III was 0.93 ± 0.22, 0.46 ± 0.16, and 0.63 ± 0.22, respectively. The level of cleaved Caspase-3/β-actin in groups II and III were significantly lower than in group I (P < .01 and P < .05, respectively). The Bcl-2/β-actin ratio for groups I, II, and III was 1.01 ± 0.09, 1.19 ± 0.39, and 1.20 ± 0.12, respectively. However, there were no significant difference between groups II and III and group I.

CONCLUSIONS

The remote perconditioning on rat hepatic IRI downregulated the Bax and cleaved Caspase-3 expression.

Applicability of endoscopic submucosal dissection for undifferentiated early gastric cancer: Mixed histology of poorly differentiated adenocarcinoma and signet ring cell carcinoma is a worse predictive factor of nodal metastasis

BACKGROUND

Endoscopic submucosal dissection (ESD) is not considered an appropriate treatment for undifferentiated early gastric cancer (UEGC) due to the higher risk of nodal metastases. We aimed to investigate predictive factors for nodal metastases in UEGCs, determine whether the tumor histology is an independent factor for it, and explore whether ESD is applicable for UEGC.

METHODS

We reviewed the medical records of 1837 patients who underwent curative gastrectomy for poorly differentiated adenocarcinoma, signet ring cell carcinoma, and a mixed type of both tumors between 2008 and 2012.

RESULTS

Nodal metastases were found in 208 (11.3%) patients. Multivariate analysis revealed that lymphovascular invasion and tumor histology were significantly associated with nodal metastases in mucosal cancers, the rates of which were higher in mixed type tumors (6.3%) than in the other two types (2.0-2.5%; p = 0.005). No nodal metastases were observed in poorly differentiated adenocarcinomas <2 cm and signet ring cell carcinomas <1 cm without lymphovascular invasion and confined to the mucosa.

CONCLUSION

Mixed type tumors should not be considered for endoscopic resection. ESD might be applicable for mucosal tumors with poorly differentiated adenocarcinoma <2 cm and signet ring cell carcinoma <1 cm without lymphovascular invasion.

Survival Benefit of Early Cancer Detection Through Regular Endoscopic Screening for De Novo Gastric and Colorectal Cancers in Korean Liver Transplant Recipients

BACKGROUND

De novo malignancy is not uncommon after liver transplantation (LT). Gastric cancer is one of the most common malignancies in both the Korean general population and LT recipients, and colorectal cancer prevalence is gradually increasing.

METHODS

Among 3690 adult recipients who underwent LT from January 1999 and December 2013, the screening patterns and prognosis of 26 cases of gastric cancer and 22 cases of colorectal cancer were analyzed.

RESULTS

For gastric cancer, the mean patient age was 54.6 ± 6.2 years at LT and 59.5 ± 6.7 years at cancer diagnosis, with a post-transplant interval of 60.2 ± 29.8 months. Patients were divided into regular (n = 18) and non-regular (n = 8) screening groups, with early cancer found in 14 and 0 patients; their 2-year survival rates after cancer diagnosis were 93.1% and 33.3% (P = .006), respectively. Endoscopic resection was successfully performed in 8 patients, all in the regular screening group. For colorectal cancer, the mean patient age was 53.3 ± 6.1 years at LT and 58.1 ± 6.7 years at cancer diagnosis, with a post-transplant interval of 54.3 ± 38.0 months. Patients were divided into regular (n = 19) and non-regular (n = 3) screening groups, with early cancer found in 12 and 0 patients; their 2-year survival rates after cancer diagnosis of 92.3% and 33.3% (P = .003), respectively. Endoscopic resection was successfully performed in 6 patients, all in the regular screening group.

CONCLUSIONS

LT recipients are strongly advised to undergo regular screening studies for various de novo malignancies, especially cancers common in the general population. Regular endoscopic screening contributes to the timely detection of gastric and colorectal cancers, improving post-treatment survival outcomes.

Additive interactions between PRKAA1 polymorphisms and Helicobacter pylori CagA infection associated with gastric cancer risk in Koreans

Although several studies reported genetic polymorphisms in protein kinase AMP‐activated alpha 1 catalytic subunit (PRKAA1) and their associations with gastric cancer risk, few have evaluated associations between Helicobacter pylori infection and PRKAA1 gene‐environment interactions. Here, we evaluated the effects of interactions between H. pylori infection and PRKAA1 polymorphisms on gastric cancer risk in Koreans. In this hospital‐based case–control study, PRKAA1 genotypes were analyzed and H. pylori infection and CagA status were examined using a serologic method in 846 pairs of gastric cancer patients and controls matched for age and sex. H. pylori seropositivity was associated with a 1.43‐fold [95% confidence interval: 1.12–1.81] increase in the risk of gastric cancer, and CagA low‐positive titers during H. pylori infection increased the risk by 1.85‐fold (95% confidence interval, 1.38–2.48). Significant positive interaction between the PRKAA1 rs13361707 genotype and H. pylori infection was verified on an additive scale [relative excess risk due to interaction, 0.55; 95% confidence interval, 0.05–1.04; P = 0.030], and the gene‐environment interaction between PRKAA1 rs13361707 and CagA status was also statistically significant (relative excess risk due to interaction, 0.50; 95% confidence interval, 0.30–0.70; P < 0.001). Our results indicated that H. pylori infection, CagA status, and PRKAA1 polymorphisms were risk factors for gastric cancer in Koreans, and that the combination of two of these factors rather than their independent effects synergistically increased the risk.

Genome-wide association study of gastric adenocarcinoma in Asia: a comparison of associations between cardia and non-cardia tumours

OBJECTIVE

Genome-wide association studies (GWAS) of gastric cancer have reported differences in single-nucleotide polymorphism (SNP) associations for tumour subtypes, particularly when divided by location into the gastric cardia versus the non-cardia.

DESIGN

Here we present results for a GWAS using 2350 East Asian gastric cancer cases divided as 1189 gastric cardia and 1027 gastric non-cardia cases and 2708 controls. We also included up to 3042 cardia cases, 4359 non-cardia cases and 7548 controls for replication from two Chinese studies and one Korean study. From the GWAS, we selected 12 top SNPs for each gastric cancer subtype, 4 top SNPs for total gastric cancer and 1 SNP in MUC1 for replication testing.

RESULTS

We observed genome-wide significant associations for rs10074991 in PRKAA1 at 5p13.1 for cardia (p=7.36×10(-12)) and non-cardia cancers (p=2.42×10(-23)) with per allele OR (95% CI) for the combined endpoint of 0.80 (0.77 to 0.83). At 6p21.1, rs2294693 near UNC5CL was significantly associated with gastric non-cardia cancer risk (p=2.50×10(-8)), with OR (95% CI) of 1.18 (1.12 to 1.26), but there was only a nominal association for cardia cancer (p=1.47×10(-2)). We also confirmed a previously reported association for rs4072037 in MUC1 with p=6.59×10(-8) for total gastric cancer and similar estimates for cardia and non-cardia cancers. Three SNPs in PSCA previously reported to be associated with gastric non-cardia cancer showed no apparent association for cardia cancer.

CONCLUSIONS

Our results suggest that associations for SNPs with gastric cancer show some different results by tumour location in the stomach.

The clinical and histopathological characteristics of early-onset basal cell carcinoma in Asians

BACKGROUND

Basal cell carcinoma (BCC) is by far the most common cancer in white populations. In addition, recent reports have demonstrated an increasing incidence of BCC in Korea. We have observed a significant number of early-onset BCC cases in which the disease occurred in patients younger than 50 years.

OBJECTIVE

To investigate the clinicopathological characteristics of early-onset BCC in an Asian population, specifically in Koreans.

METHODS

One hundred and five patients with early-onset BCC were enrolled from a total of 1047 BCC patients who underwent surgery between January 1997 and December 2014 (942 patients over the age of 50 years were designated as the control group).

RESULTS

Early-onset BCC accounted for 10.03% of all 1047 cases and the incidence over time displayed an incremental trend. The early-onset group displayed similar results as the control group, with a predominance of female BCC patients and the majority of tumours displaying the following characteristics: small in size, occurring in sun-exposed areas and belonging to the noduloulcerative clinical subtype and nodular histopathological subtype. In comparison with a previous study in a Western population, the incidence of the disease in non-exposed areas of the body, as well as the proportion of tumours of the superficial histological subtype, were lower in Asian patients.

CONCLUSION

Although the clinicopathological characteristics of BCC are well-known, these characteristics have not been determined for early-onset BCC in an Asian population. Therefore, this study is the first report on early-onset BCC in Asians, specifically in a Korean patient group.

Comparative Proteomic Analysis of Rapamycin Versus Cyclosporine Combination Treatment in Mouse Podocytes

BACKGROUND

The mechanism of podocyte injury observed with the use of rapamycin (RPM) remains unclear. The conversion from calcineurin inhibitors (CNIs) to RPM in kidney transplant recipients has been associated with a higher incidence of proteinuria and renal injury. In this study, we performed proteomic analyses to investigate the alteration of protein expression in mouse podocytes treated with RPM in comparison with CNI/RPM combination.

METHODS

Immortalized mouse podocytes were treated with 20 nmol/L RPM or 20 nmol/L RPM + 1 μg/mL cyclosporine. Podocyte proteins were separated by 2-dimensional polyacrylamide gel electrophoresis (2DE) and identified by matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry and peptide fingerprinting. Selected proteins were analyzed by means of Western blot assay.

RESULTS

We identified 36 differently expressed proteins after isolated RPM or CNI/RPM combination treatment in cultured mouse podocytes. There are 3 distinct patterns of protein expression: (1) potentiated down- or upregulation of proteins by CNI/RPM treatment compared with isolated RPM treatment (n = 4); (2) partial offset of down-regulation by CNI/RPM in comparison with RPM treatment (n = 25); (3) no difference in down-regulation between RPM and CNI/RPM treatment (n = 5). We found a significant interplay between RPM and CNI on the expression of the selected proteins in mouse podocytes. This might explain the higher incidence of proteinuria by CNI/RPM combination in clinical settings.

CONCLUSIONS

Further study is required to elucidate the target protein associated with RPM-induced podocyte injury.

Concurrent Post-Transplantation Diabetes Mellitus in Renal Allograft Recipients With Immunoglobulin A Nephropathy

BACKGROUND

The prevalence of post-transplantation immunoglobulin A nephropathy (PTIgAN) and diabetes mellitus (PTDM) increases with time after transplantation, and recognition and management of these conditions is becoming more important in renal allograft recipients as graft survival increases.

METHODS

We explored the influence of concurrent PTDM on renal allograft histology and function in 111 cases with PTIgAN diagnosed from 2000 to 2010 at our institution.

RESULTS

Sixteen patients (14.4%) had PTDM at the time of diagnosis of PTIgAN, which increased to 28 patients (25.2%) at the last follow-up (10.4 years after transplantation). Donor ages were younger in PTIgAN patients with concurrent PTDM. However, other clinical and demographic data were not significantly different between PTIgAN patients with and without PTDM. Histologically, Banff "mm" scores were higher and "M1" of the Oxford classification was more frequent in PTIgAN patients with concurrent PTDM than in patients without PTDM, but the difference did not reach statistical significance. Serum creatinine levels and proteinuria at the time of biopsy and overall graft survival did not vary according to the presence of PTDM both at biopsy and at the last follow-up.

CONCLUSIONS

Concurrent PTDM does not significantly influence graft function or outcome for 10 years after transplantation in PTIgAN patients.

Superconductivity below 20 K in heavily electron-doped surface layer of FeSe bulk crystal

A superconducting transition temperature (T_c) as high as 100 K was recently discovered in one monolayer FeSe grown on SrTiO₃. The discovery ignited efforts to identify the mechanism for the markedly enhanced T_c from its bulk value of 8 K. There are two main views about the origin of the T_c enhancement: interfacial effects and/or excess electrons with strong electron correlation. Here, we report the observation of superconductivity below 20 K in surface electron-doped bulk FeSe. The doped surface layer possesses all the key spectroscopic aspects of the monolayer FeSe on SrTiO₃. Without interfacial effects, the surface layer state has a moderate T_c of 20 K with a smaller gap opening of 4.2 meV. Our results show that excess electrons with strong correlation cannot induce the maximum T_c, which in turn reveals the need for interfacial effects to achieve the highest T_c in one monolayer FeSe on SrTiO₃.

Thin FeSe film on SrTiO₃ substrate becomes a superconductor with a transition temperature over 100 K, yet the origin remains controversial. Here, Seo et al. show superconductivity below 20 K on the electron-doped surface of an FeSe crystal, suggesting a decisive role of interfacial effects in the enhancement of superconductivity.

Antifungal activity of rimocidin and a new rimocidin derivative BU16 produced by Streptomyces mauvecolor BU16 and their effects on pepper anthracnose

AIMS

The objective of this study was to explore antifungal metabolites targeting fungal cell envelope and to evaluate the control efficacy against anthracnose development in pepper plants.

METHODS AND RESULTS

A natural product library comprising 3000 microbial culture extracts was screened via an adenylate kinase (AK)-based cell lysis assay to detect antifungal metabolites targeting the cell envelope of plant-pathogenic fungi. The culture extract of Streptomyces mauvecolor strain BU16 displayed potent AK-releasing activity. Rimocidin and a new rimocidin derivative, BU16, were identified from the extract as active constituents. BU16 is a tetraene macrolide containing a six-membered hemiketal ring with an ethyl group side chain instead of the propyl group in rimocidin. Rimocidin and BU16 showed broad-spectrum antifungal activity against various plant-pathogenic fungi and demonstrated potent control efficacy against anthracnose development in pepper plants.

CONCLUSIONS

Antifungal metabolites produced by S. mauvecolor strain BU16 were identified to be rimocidin and BU16. The compounds displayed potent control efficacy against pepper anthracnose.

SIGNIFICANCE AND IMPACT OF THE STUDY

Rimocidin and BU16 would be active ingredients of disease control agents disrupting cell envelope of plant-pathogenic fungi. The structure and antifungal activity of rimocidin derivative BU16 is first described in this study.

Risk factors for selection of patients at high risk of recurrence or death after complete surgical resection in stage I gastric cancer

BACKGROUND

The therapeutic benefit of adjuvant chemotherapy has not been proven in stage I gastric cancer (GC). The aim of this study was to identify stage I GC patients at high risk of recurrence or death.

METHODS

We retrospectively reviewed the medical records of 2,783 patients with pathologically confirmed stage I GC who underwent curative surgical resection alone at Asan Medical Center between 2003 and 2007. The clinicopathologic parameters explored included age, sex, histologic differentiation, Lauren classification, size, location, multiplicity, stage, lymphovascular or perineural invasion, preoperative serum levels of tumor markers (carcinoembryonic antigen, carbohydrate antigen 19-9, carbohydrate antigen 72-4), and type of surgery.

RESULTS

With a median follow-up of 54 months (range 0-60 months), 212 patients (7.6%) experienced recurrence or death, and the 5 -year recurrence-free survival (RFS) rate and overall survival rate were 89.9 and 93.4%, respectively. With a multivariate analysis, six factors (age over 65 years, male gender, stage IB GC, lymphovascular invasion, perineural invasion, and elevated level of carcinoembryonic antigen) were independent poor prognostic factors for RFS (p < 0.05). Patients with more than two of six poor risk factors had a 5-year RFS rate of 79%, whereas patients with fewer risk factors had a 5-year RFS rate of 97% (p <0.001).

CONCLUSIONS

In this study cohort, we identified six independent risk factors for RFS. The patients with more than two risk factors are expected to have significant risk of recurrence or death after curative resection and should be considered as candidates for adjuvant treatment.