Polymorphic Self-Assembly with Procedural Flexibility for Monodisperse Quaternary Protein Structures of DegQ Enzymes

As large molecular tertiary structures, some proteins can act as small robots that find, bind, and chaperone target protein clients, showing the potential to serve as smart building blocks in self-assembly fields. Instead of using such intrinsic functions, most self-assembly methodologies for proteins aim for de novo-designed structures with accurate geometric assemblies, which can limit procedural flexibility. Here, a strategy enabling polymorphic clustering of quaternary proteins, exhibiting simplicity and flexibility of self-assembling paths for proteins in forming monodisperse quaternary cage particles is presented. It is proposed that the enzyme protomer DegQ, previously solved at low resolution, may potentially be usable as a threefold symmetric building block, which can form polyhedral cages incorporated by the chaperone action of DegQ in the presence of protein clients. To obtain highly monodisperse cage particles, soft, and hence, less resistive client proteins, which can program the inherent chaperone activity of DegQ to efficient formations of polymorphic cages, depending on the size of clients are utilized. By reconstructing the atomic resolution cryogenic electron microscopy DegQ structures using obtained 12- and 24-meric clusters, the polymorphic clustering of DegQ enzymes is validated in terms of soft and rigid domains, which will provide effective routes for protein self-assemblies with procedural flexibility.

Cargo specificity, regulation, and therapeutic potential of cytoplasmic dynein

Intracellular retrograde transport in eukaryotic cells relies exclusively on the molecular motor cytoplasmic dynein 1. Unlike its counterpart, kinesin, dynein has a single isoform, which raises questions about its cargo specificity and regulatory mechanisms. The precision of dynein-mediated cargo transport is governed by a multitude of factors, including temperature, phosphorylation, the microtubule track, and interactions with a family of activating adaptor proteins. Activating adaptors are of particular importance because they not only activate the unidirectional motility of the motor but also connect a diverse array of cargoes with the dynein motor. Therefore, it is unsurprising that dysregulation of the dynein-activating adaptor transport machinery can lead to diseases such as spinal muscular atrophy, lower extremity, and dominant. Here, we discuss dynein motor motility within cells and in in vitro, and we present several methodologies employed to track the motion of the motor. We highlight several newly identified activating adaptors and their roles in regulating dynein. Finally, we explore the potential therapeutic applications of manipulating dynein transport to address diseases linked to dynein malfunction.

Discovery of N-benzylbenzamide-based allosteric inhibitors of Aurora kinase A

Aurora kinases (AurkA/B/C) regulate the assembly of bipolar mitotic spindles and the fidelity of chromosome segregation during mitosis, and are attractive therapeutic targets for cancers. Numerous ATP-competitive AurkA inhibitors have been developed as potential anti-cancer agents. Recently, a few allosteric inhibitors have been reported that bind to the allosteric Y-pocket within AurkA kinase domain and disrupt the interaction between AurkA and its activator TPX2. Herein we report a novel allosteric AurkA inhibitor (6h) of N-benzylbenzamide backbone. Compound 6h suppressed the both catalytic activity and non-catalytic functions of AurkA. The inhibitory activity of 6h against AurkA (IC50 = 6.50 μM) was comparable to that of the most potent allosteric AurkA inhibitor AurkinA. Docking analysis against the Y-pocket revealed important pharmacophores and interactions that were coherent with structure-activity relationship. In addition, 6h suppressed DNA replication in G1-S phase, which is a feature of allosteric inhibition of AurA. Our current study may provide a useful insight in designing potent allosteric AurkA inhibitors.

Protective effects of esomeprazole against cisplatin-induced ototoxicity: an in vitro and in vivo study

In this study, we aimed to identify novel compounds that could afford protection against cisplatin-induced ototoxicity by employing both cell- and zebrafish (Danio rerio)-based screening platforms. We screened 923 US Food and Drug Administration-approved drugs to identify potential compounds exhibiting protective effects against cisplatin-induced ototoxicity in HEI-OC1 cells (auditory hair cell line). The screening strategy identified esomeprazole and dexlansoprazole as the primary hit compounds. Subsequently, we examined the effects of these compounds on cell viability and apoptosis. Our results revealed that esomeprazole and dexlansoprazole inhibited organic cation transporter 2 (OCT2), thus providing in vitro evidence that these compounds could ameliorate cisplatin-induced ototoxicity by directly inhibiting OCT2-mediated cisplatin transport. In vivo, the protective effects were validated using zebrafish; esomeprazole was found to decrease cisplatin-induced hair cell damage in neuromasts. Furthermore, the esomeprazole-treated group showed a significantly lower number of TUNEL-positive cells than the cisplatin-treated group. Collectively, our findings revealed that esomeprazole exerts a protective effect against cisplatin-induced hair cell damage in both HEI-OC1 cells and a zebrafish model.

Structural basis for CEP192-mediated regulation of centrosomal AURKA

Aurora kinase A (AURKA) performs critical functions in mitosis. Thus, the activity and subcellular localization of AURKA are tightly regulated and depend on diverse factors including interactions with the multiple binding cofactors. How these different cofactors regulate AURKA to elicit different levels of activity at distinct subcellular locations and times is poorly understood. Here, we identified a conserved region of CEP192, the major cofactor of AURKA, that mediates the interaction with AURKA. Quantitative binding studies were performed to map the interactions of a conserved helix (Helix-1) within CEP192. The crystal structure of Helix-1 bound to AURKA revealed a distinct binding site that is different from other cofactor proteins such as TPX2. Inhibiting the interaction between Helix-1 and AURKA in cells led to the mitotic defects, demonstrating the importance of the interaction. Collectively, we revealed a structural basis for the CEP192-mediated AURKA regulation at the centrosome, which is distinct from TPX2-mediated regulation on the spindle microtubule.

Cardiovascular benefit of lowering LDL-C below 1 mmol/L (40 mg/dl)

Background

The 2019 ESC/EAS Dyslipidemia Guidelines recommend an LDL-C goal of <1.4 mmol/L (∼55 mg/dl) for patients with very high-risk ASCVD, and <1 mmol/L (∼40 mg/dl) for those with recurrent events within 2 years despite taking maximally tolerated statin therapy. The addition of PCSK9 inhibitors to statin therapy can achieve LDL-C levels well below 1 mmol/L in many patients, yet the clinical benefit of LDL-C lowering beyond this level has recently been questioned.

Methods

FOURIER was a cardiovascular outcomes trial comparing evolocumab vs. placebo in patients with stable ASCVD on optimized statin therapy with a median follow-up of 2.2 years. We performed an exploratory analysis to determine the consistency of CV risk reduction with LDL-C lowering below ∼1 mmol/L (40 mg/dl) with evolocumab. We modeled the achieved LDL-C at 48 weeks in the two treatment arms as well as the percentage of LDL-C difference between the two arms that was due to LDL-C below ∼1 mmol/L (40 mg/dl) as a function of baseline LDL-C. We then modeled the hazard ratio (HR) for the composite of CV death, MI or stroke (per 1 mmol/L reduction in LDL-C) with evolocumab vs. placebo as a function of baseline LDL-C.

Results

All 27,564 patients from FOURIER were included in this analysis. Patients with lower baseline LDL-C achieved lower LDL-C levels following evolocumab therapy, with achieved LDL-C typically being below 1 mmol/L (40 mg/dl) once the baseline LDL-C was below 2.4 mmol/L (94 mg/dl) and reaching levels approaching 0.5 mmol/L (∼20 mg/dl). Accordingly, the further baseline LDL-C levels were below 2.4 mmol/L (94 mg/dl), the greater the proportion of the difference in achieved LDL-C between the evolocumab and placebo arms was due to LDL-C levels below ∼1 mmol/L (40 mg/dl), reaching nearly 40% of the difference in LDL-C between treatment arms (Upper Panel). Despite this, the clinical benefit of LDL-C lowering was not attenuated (p=0.78) (and even appeared greater), with robust reductions in risk of CV death, MI or stroke even when LDL-C was lowered to nearly 0.5 mmol/L (∼20 mg/dl) and having close to 40% of the LDL-C difference between treatment arms due to LDL-C lowering below ∼1 mmol/L (40 mg/dl) (Lower Panel).

Conclusion

PCSK9 inhibitors added to statin therapy can achieve LDL-C well below 1 mmol/L (40 mg/dl). There is no evidence for attenuation of the clinical benefit of lowering LDL-C below this threshold. These data support lowering LDL-C to below 1 mmol/L (40 mg/dl) in patients with ASCVD.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Health

0695 Sleepwell24, A Smartphone Application To Promote PAP Therapy Adherence: Feasibility And Acceptability

Introduction

We aimed to test the feasibility and acceptability of SleepWell24, a multicomponent, smartphone-delivered intervention to increase positive airway pressure (PAP) adherence among newly diagnosed OSA patients.

Methods

SleepWell24 targets PAP adherence along with other health behaviors through education, trouble-shooting, goal-setting, and near real-time biofeedback of PAP machine use, and sleep and physical activity levels (via Fitbit integration), and other chronic disease self-management components. Patients with a first-time diagnosis of OSA (AHI≥5) and prescribed PAP therapy were enrolled from the Centers for Sleep Medicine at Mayo Clinic in Rochester, MN and Phoenix, AZ. Patients were randomized to SleepWell24 or usual care (UC) and assessed for PAP use over 60 consecutive nights. UC patients received a Fitbit monitor to control for non-specific intervention effects related to the introduction of a new personal technology. Feasibility was assessed with recruitment and retention rates and acceptability was assessed post-intervention with the validated, 8-item Treatment Evaluation Questionnaire (TEQ; range:0-4). ANCOVA models, adjusting for age, sex, and AHI severity, compared intervention arms on acceptability ratings.

Results

OSA patients were consented and randomized (N=111). Before the intervention began 4 participants withdrew, 12 were lost to follow-up, and 5 could not start the trial due to durable medical equipment (DME) vendor barriers. Ninety OSA patients (n=41 SleepWell24, n=49 UC; age M±SD=57.2±12.2; 44.4% female, 61.1% AHI≥15) started the intervention, with 2 participants withdrawing, 1 becoming deceased (unrelated to treatment) and 7 with missing PAP data due to DME vendor barriers. There was no significant between-groups differences on post-treatment acceptability (SleepWell24 M±SD=2.7±1.1 vs. UC M±SD=3.1±0.9, F[1,73]=2.3, p=0.11), and 77% of SleepWell24 participants found the app to be moderately to totally acceptable.

Conclusion

Overall, SleepWell24 was found to be feasible for delivery in two large clinical sleep medicine centers, and patients found the app to be acceptable. A number of challenges in trial delivery were encountered that have implications for scaled-up efficacy testing: (a) partnerships with DME vendors for near real-time PAP data integration; (b) alignment with clinical practice (i.e., referral, medical record integration); and (c) patient engagement.

Support

National Institute of Nursing Research / National Institutes of Health: R21NR016046

Influence of esophagectomy on the gastroesophageal reflux in patients with esophageal cancer

This study aims to assess the influence of esophagectomy with gastric transposition on the gastroesophageal reflux (GER) and gastric acidity in patients with esophageal cancer. Data on 53 esophageal cancer patients who underwent 24-hour impedance-pH monitoring after esophagectomy were retrospectively analyzed. We used a solid-state esophageal pH probe in which the esophageal pH sensor is placed 1.5 cm distal to the upper esophageal sphincter and the gastric pH sensor is located 15 cm distal to the esophageal pH channel. 24-hour impedance-pH monitoring data and other clinical data including anastomosis site stricture and incidence of pneumonia were collected. We defined pathologic reflux with reference to known normative data. Stricture was defined when an intervention such as bougienage or balloon dilatation was required to relieve dysphagia. The esophageal and gastric mean pH were 5.47 ± 1.51 and 3.33 ± 1.64, respectively. The percent time of acidic pH (<4) was 6.66 ± 12.49% in the esophagus and 70.53 ± 32.19% in the stomach. Esophageal pathologic acid reflux was noticed in 32.1%, 20.8%, and 35.8% during total, upright, and recumbent time, respectively. Esophageal pathologic bolus reflux was noted in 83.0%, 77.4%, and 64.2% during total, upright, and recumbent time, respectively. Gastric acidity increased with time after esophagectomy. Esophageal acid exposure time correlated with intragastric pH. However, esophageal pathologic acid reflux was not associated with anastomosis site stricture or pneumonia. In conclusion, GER frequently occurs after esophagectomy. Thus, strict lifestyle modifications and acid suppression would be necessary in patients following esophagectomy.

Early complications after percutaneous radiofrequency ablation for hepatocellular carcinoma: an analysis of 1,843 ablations in 1,211 patients in a single centre: experience over 10 years

AIM

To evaluate the incidence of adverse events and associated factors after radiofrequency ablation (RFA) in patients with hepatocellular carcinoma within 30 days.

MATERIALS AND METHODS

The early complications that occurred within 30 days after RFA at a single institution from January 2000 to July 2010 were reviewed in order to evaluate the morbidity, mortality, and risk factors associated with the complications. In total, 1,211 patients (845 men, 70.5%) with a mean age of 68 years (range, 27-88 years) underwent 1,843 RFA procedures.

RESULTS

The overall incidence rate of complications was 6.8% (125 cases). Major complications (n=36, 2%) included liver abscess (n=15, 0.8%), intraperitoneal bleeding (n=8, 0.4%), liver failure (n=5, 0.3%), variceal bleeding (n=3, 0.2%), haemothorax (n=2, 0.1%), cholecystitis (n=2, 0.1%), and bowel perforation (n=1, 0.1%). Among the minor complications (n=89, 4.8%), the most common was the post RFA syndrome accompanied by pain and fever (n=75, 4.1%). Other minor complications included significant pleural effusion (n=7, 0.4%), skin wound infection (n=4, 0.2%), and thermal injuries to the skin (n=3, 0.2%). Procedural infections significantly increased with tumour size (OR=1.379; 95% confidence interval [CI], 1.191-1.579; p<0.001), and multiple overlapping ablations (OR=1.118; 95% CI, 1.019-1.227, p=0.018). Thrombocytopenia (<50,000/μl), prothrombin time, and serum albumin level were significantly associated with post-RFA bleeding episodes (p=0.041, p=0.021, and p=0.003, respectively). The overall mortality rate was 0.3% (three cases of hepatic failure, two case of sepsis, and one case of renal failure).

CONCLUSIONS

RFA is a safe and effective local treatment for hepatocellular carcinoma. Careful selection of patients and appropriate RFA planning could decrease procedural mortality and morbidity.

Abstract P5-02-04: Plasma autoantibodies associated with basal-like breast cancers

Background: Basal-like breast cancer (BLBC) is a rare aggressive subtype that is less likely to be detected through mammographic screening. Identification of circulating markers associated with BLBC could have promise in detecting and managing this deadly disease.

Methods: Using samples from the Polish Breast Cancer study, a high-quality population-based case-control study of breast cancer, we screened 10,000 antigens on protein arrays using 45 BLBC patients and 45 controls, and identified 748 promising plasma autoantibodies (AAbs) associated with BLBC. ELISA assays of promising markers were performed on a total of 145 BLBC cases and 145 age-matched controls. Sensitivities at 98% specificity were calculated and a BLBC classifier was constructed.

Results: We identified a 13-AAbs (CTAG1B, CTAG2, TP53, RNF216, PPHLN1, PIP4K2C, ZBTB16, TAS2R8, WBP2NL, DOK2, PSRC1, MN1, TRIM21) that distinguished BLBC from controls with 33% sensitivity and 98% specificity. We also discovered a strong association of TP53 AAb with its protein expression (p=0.009) in BLBC patients. In addition, MN1 and TP53 AAbs were associated with worse survival (MN1 AAb marker HR=2.25 95%CI= 1.03-4.91 p=0.04; TP53, HR=2.02, 95%CI 1.06-3.85, p=0.03). We found limited evidence that AAb levels differed by demographic characteristics.

Conclusions: These AAbs warrant further investigation in clinical studies to determine their value for further understanding the biology of BLBC and possible detection. Currently, they are also being tested in a large national blind validation trial using a well characterized independent sample set.

Citation Format: Wang (Student) J, Figueroa JD, Wallstrom G, Barker K, Park JG, Demirkan G, Lissowska J, Anderson K, Qiu J, LaBaer J. Plasma autoantibodies associated with basal-like breast cancers. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-02-04.

Tumour volume changes assessed with high-quality KVCT in lung cancer patients undergoing concurrent chemoradiotherapy

OBJECTIVE

We evaluated tumour volume changes in patients with lung cancer undergoing concurrent chemoradiotherapy using image-guided radiotherapy (RT).

METHODS

The kilovoltage image was obtained using CT on rail at every five fractions. The gross tumour volumes (GTVs), including the primary tumour and lymph nodes (LNs), were contoured to analyse the time and degree of tumour regression.

RESULTS

46 patients [32, non-small-cell lung cancer (NSCLC), and 14, small-cell lung cancer (SCLC)] were included in this study. In total, 281 CT scans and 82 sites of GTVs were evaluated. Significant volume changes occurred in both the NSCLC and SCLC groups (p < 0.001 and 0.002), and the average GTV change compared with baseline was 49.85 ± 3.65 [standard error (SE)]% and 65.95 ± 4.60 (SE)% for the NSCLC and SCLC groups, respectively. A significant difference in the degree of volume reduction between the primary tumour and LNs was observed in only the NSCLC group (p < 0.0001) but not in the SCLC group (p = 0.735). The greatest volume regression compared with the volume before the five fractions occurred between the 15 and 20 fractions in the NSCLC group and between the 5 and 10 fractions in the SCLC group.

CONCLUSION

Both primary tumour and LNs were well defined using CT on rail. Significant volume changes occurred during RT, and there was a difference in volume reduction between the NSCLC and SCLC groups, regarding the degree and timing of the tumour reduction in the primary tumour and LNs.

ADVANCES IN KNOWLEDGE

NSCLC and SCLC groups showed differences in the degree and timing of volume reduction. The primary tumour and LNs in NSCLC regressed differently.

Recurrent lactic acidosis secondary to hand sanitizer ingestion

Due to their ability to decrease the spread of infection, hand sanitizers are now ubiquitous in health care settings. We present the case of a 50-year-old woman who was admitted with acute alcohol intoxication and had near complete recovery in 12 hrs. Subsequently, she was found unresponsive on the floor of her hospital room on two separate occasions. Evaluations revealed repeatedly elevated levels of ethanol, acetone, and lactate as well as increased anion gap and hypotension, requiring intensive care unit evaluation and intubation for airway protection. During the second episode, she was found next to an empty bottle of ethanol-based hospital hand sanitizer. She confirmed ingesting hand sanitizer in order to become intoxicated.

Low doses of the novel caspase-inhibitor GS-9450 leads to lower caspase-3 and -8 expression on peripheral CD4+ and CD8+ T-cells

Chronic hepatitis C virus (HCV) infection is characterized by increased rates of apoptotic hepatocytes and activated caspases have been shown in HCV-infected patients. GS-9450, a novel caspase-inhibitor has demonstrated hepatoprotective activity in fibrosis/apoptosis animal models. This study evaluated the effects of GS-9450 on peripheral T-cell apoptosis in chronic HCV-infected patients. As sub study of the GS-US-227-0102, a double-blind, placebo-controlled phase 2a trial evaluating the safety and tolerability of GS-9450, apoptosis of peripheral CD4+ and CD8+ T-cells was measured using activated caspase-3, activated caspase-8 and CD95 (Fas). Blood samples were drawn at baseline, day 14 after therapy and at 5 weeks off-treatment follow-up in the first cohort of 10 mg. In contrast to the placebo-treated patients, GS-9450 caused a median of 46% decrease in ALT-values from baseline to day 14 in all treated patients (median of 118-64 U/l) rising again to a median of 140 U/l (19%) at 5 weeks off-treatment follow-up. In GS9450-treated patients, during treatment and follow-up, percentages of activated caspase-3+ and caspase-8 expression tended to decrease, in contrast to placebo-treated patients. Interestingly, compared to healthy controls, higher percentages of caspase-3 and caspase-8 positive CD4+ and CD8+ T-cells were demonstrated in HCV-infected patients at baseline. Decreased ALT-values were observed in all HCV-infected patients during treatment with low dose of the caspase-inhibitor GS-9450 accompanied by a lower expression of caspase-3 and -8 on peripheral T-cells. Furthermore, at baseline percentages of activated caspase-3, activated caspase-8 and CD95+ T-cells were higher in chronic HCV-infected patients compared to healthy controls.

Common variant in 6q26-q27 is associated with distal colon cancer in an Asian population

BACKGROUND AND AIM

Colorectal cancer (CRC) is a multifactorial disease with both environmental and genetic factors contributing to its development. The incidence of CRC is increasing year by year in Japan. Patients with CRC in advanced stages have a poor prognosis, but detection of CRC at earlier stages can improve clinical outcome. Therefore, identification of epidemiologial factors that influence development of CRC would facilitate the prevention or early detection of disease.

METHODS

To identify loci associated with CRC risk, we performed a genome-wide association study (GWAS) for CRC and sub-analyses by tumour location using 1583 Japanese CRC cases and 1898 controls. Subsequently, we conducted replication analyses using a total of 4809 CRC cases and 2973 controls including 225 Korean subjects with distal colon cancer and 377 controls.

RESULTS

We identified a novel locus on 6q26-q27 region (rs7758229 in SLC22A3, p = 7.92 × 10⁻⁹, OR of 1.28) that was significantly associated with distal colon cancer. We also replicated the association between CRC and SNPs on 8q24 (rs6983267 and rs7837328, p = 1.51 × 10⁻⁸ and 7.44 × 10⁻⁸, ORs of 1.18 and 1.17, respectively). Moreover, we found cumulative effects of three genetic factors (rs7758229, rs6983267, and rs4939827 in SMAD7) and one environmental factor (alcohol drinking) which appear to increase CRC risk approximately twofold.

CONCLUSIONS

We found a novel susceptible locus in SLC22A3 that contributes to the risk of distal colon cancer in an Asian population. These findings would further extend our understanding of the role of common genetic variants in the aetiology of CRC.

Electrical conductivity modeling and experimental study of densely packed SWCNT networks

Single-walled carbon nanotube (SWCNT) networks have become a subject of interest due to their ability to support structural, thermal and electrical loadings, but to date their application has been hindered due, in large part, to the inability to model macroscopic responses in an industrial product with any reasonable confidence. This paper seeks to address the relationship between macroscale electrical conductivity and the nanostructure of a dense network composed of SWCNTs and presents a uniquely formulated physics-based computational model for electrical conductivity predictions. The proposed model incorporates physics-based stochastic parameters for the individual nanotubes to construct the nanostructure such as: an experimentally obtained orientation distribution function, experimentally derived length and diameter distributions, and assumed distributions of chirality and registry of individual CNTs. Case studies are presented to investigate the relationship between macroscale conductivity and nanostructured variations in the bulk stochastic length, diameter and orientation distributions. Simulation results correspond nicely with those available in the literature for case studies of conductivity versus length and conductivity versus diameter. In addition, predictions for the increasing anisotropy of the bulk conductivity as a function of the tube orientation distribution are in reasonable agreement with our experimental results. Examples are presented to demonstrate the importance of incorporating various stochastic characteristics in bulk conductivity predictions. Finally, a design consideration for industrial applications is discussed based on localized network power emission considerations and may lend insight to the design engineer to better predict network failure under high current loading applications.

In vitro performance of nano-heterogeneous dentin adhesive

Water is ubiquitous in the mouths of healthy individuals and routinely interferes with efforts to bond restorations to dental tissues. Our previous studies using tapping-mode atomic force microscopy (TMAFM) have shown that nanophase separation is a general feature of cross-linked polymethacrylates photocured in the presence of water. To explore the relationship between nanophase separation in dentin adhesives and their long-term mechanical properties, we evaluated model adhesives after 3 months of aqueous storage. The degree of contrast in the TMAFM phase image depended on the formulations used, ranging from 'not observable' to 'very strong'. Correspondingly, the mechanical properties of these model adhesives varied from 'minimal change' to 'significant depreciation'. The results support the hypothesis that a high degree of heterogeneity at the nano-scale is associated with poor mechanical durability in these model adhesives.

Synchronous gastric cancer in primary sporadic colorectal cancer patients in Korea

BACKGROUND AND AIMS

Colorectal cancer has been reported to be the malignancy most frequently associated with gastric cancer in Korea. The aim of this study was to define the frequency and clinical characteristics of synchronous gastric cancer detected at preoperative esophagogastroduodenoscopy (EGD) in colorectal cancer patients.

MATERIALS AND METHODS

This prospective study analyzed the EGD results from 1,542 consecutive colorectal cancer patients who underwent surgery from January 2003 to December 2005 at the Center for Colorectal Cancer, National Cancer Center, Korea.

RESULTS

Of the 1,542 cases, 1,155 (74.9%) underwent EGD at our center and 387 underwent EGD at other hospitals within 6 months before surgery. Of the 1,542 cases, synchronous gastric cancers were detected in 31 cases (2.0%). Of these 31 cases, 26 had early gastric cancer (EGC; 83.9%) and 5 had advanced gastric cancer. Ten (38.5%) of the 26 EGC cases were managed using endoscopic mucosal resection. Compared to colorectal cancer patients without synchronous gastric cancer, the group of patients with synchronous gastric cancer was older (65.5+/-9.6 vs 58.4+/-11.3 years, p=0.001) and had a greater proportion of males (77.4 vs 59.4%, p=0.043).

CONCLUSION

This study found that 2% of Korean sporadic colorectal cancer patients had synchronous gastric cancer. A preoperative EGD for colorectal cancer patients is likely to greatly assist in the diagnosis of synchronous gastric cancer at an early stage and the implementation of appropriate minimally invasive treatment.

Pathologic gambling in patients with restless legs syndrome treated with dopaminergic agonists

Pathologic gambling is an impulse control disorder previously reported to complicate dopamine agonist therapy in patients with Parkinson disease. It has not been described in association with dopamine agonist therapy of other conditions. We report three patients treated in our sleep disorders center who developed pathologic gambling while receiving treatment with dopamine agonists for restless legs syndrome.

Fabrication and mechanical properties of suspended one-dimensional polymer nanostructures: polypyrrole nanotube and helical polyacetylene nanofibre

Mechanical properties of suspended quasi-one-dimensional polymer nanostructures were investigated using atomic force microscopy (AFM). A recently developed new acid-free etch method combined with electron beam lithography was used to fabricate suspended polypyrrole (PPy) nanotubes and helical polyacetylene (HPA) nanofibres. The elastic modulus of each suspended structure was obtained by AFM force-distance measurements. The estimated modulus value of the PPy nanotube (HPA nanofibre) was 0.96 GPa (0.5 GPa). Using this acid-free method, all-organic flexible NEMS devices can be fabricated in the future.

Congenital stridor: unusual manifestation of coarctation of the aorta

Coarctation of the aorta is a relatively common congenital condition. Most infantile presentations of aortic coarctation are related to the associated congenital cardiac abnormalities leading to congestive heart failure or systemic hypoperfusion. We describe a 4-month-old infant who presented with stridor as the sole manifestation of coarctation. Radiologic studies revealed enlarged innominate artery due to the aortic coarctation that resulted in tracheal compression. After surgical correction, respiratory signs and symptoms completely resolved. This case report describes a unique cause of stridor in newborn infants and discusses the potential for vascular anomalies to result in tracheal narrowing.

Analysis of insulin signalling by RNAi-based gene silencing

Using siRNA-mediated gene silencing in cultured adipocytes, we have dissected the insulin-signalling pathway leading to translocation of GLUT4 glucose transporters to the plasma membrane. RNAi (RNA interference)-based depletion of components in the putative TC10 pathway (CAP, CrkII and c-Cbl plus Cbl-b) or the phospholipase Cγ pathway failed to diminish insulin signalling to GLUT4. Within the phosphoinositide 3-kinase pathway, loss of the 5′-phosphatidylinositol 3,4,5-trisphosphate phosphatase SHIP2 was also without effect, whereas depletion of the 3′-phosphatase PTEN significantly enhanced insulin action. Downstream of phosphatidylinositol 3,4,5-trisphosphate and PDK1, silencing the genes encoding the protein kinases Akt1/PKBα, or CISK(SGK3) or protein kinases Cλ/ζ had little or no effect, but loss of Akt2/PKBβ significantly attenuated GLUT4 regulation by insulin. These results show that Akt2/PKBβ is the key downstream intermediate within the phosphoinositide 3-kinase pathway linked to insulin action on GLUT4 in cultured adipocytes, whereas PTEN is a potent negative regulator of this pathway.

PTEN gene mutations in colorectal cancers displaying microsatellite instability

To determine the relationship between the mutation of the PTEN gene and genomic instability in human colorectal cancer, we screened the PTEN gene in 32 colorectal cancers (eight cell lines and 24 tissues) displaying microsatellite instability (MSI) and 32 colorectal cancers (six cell lines and 26 tissues) displaying microsatellite stability (MSS). Of 64 samples, six frameshift mutations were identified in six MSI colorectal cancers (two cell lines and four tumor tissues) but not in MSS colorectal cancers. Of the six MSI colorectal cancers containing PTEN mutation, two case (one cell line and one tumor tissue) showed biallelic mutation of PTEN. Furthermore, to compare the frequency of PTEN mutation with that of other MSI target genes, the mononucleotide repeat sequences of TGF-betaRII, BAX, IGFIIR, hMSH6 and hMSH3 were analyzed. The frequencies of frameshift mutation were revealed 78% in TGF-betaRII, 56% in BAX, 46.9% in hMSH3, 37.5% in hMSH6, 21.9% in IGFIIR, and 18.8% in PTEN. These results suggest that the PTEN gene is a target of genomic instability in MSI colorectal tumorigenesis.

PYK2 as a mediator of endothelin-1/G alpha 11 signaling to GLUT4 glucose transporters

Endothelin-1 (ET-1) signaling through G alpha(q/11) stimulates translocation of intracellular GLUT4 glucose transporters to the plasma membrane of 3T3-L1 adipocytes by an unknown mechanism that requires protein tyrosine phosphorylation and ADP-ribosylation factor 6 (ARF6) but is independent of phosphatidylinositol 3 (PI3)-kinase. In contrast, insulin action on this process requires PI3-kinase but not ARF6. Here we report the identification of two proteins selectively tyrosine-phosphorylated in response to ET-1 but not insulin: the Ca(2+)-activated tyrosine kinase PYK2 and its physiological substrate, the adhesion scaffold protein paxillin. Endogenous paxillin as well as expressed Myc-tagged PYK2 or a Myc-tagged kinase-deficient PYK2 protein were acutely directed to F-actin-rich adhesion sites from the adipocyte cytoplasm in response to ET-1 but not insulin. CADTK-related non-kinase (CRNK) is a dominant negative form of PYK2 containing the C-terminal portion of the protein, which binds paxillin but lacks the PYK2 autophosphorylation site (Tyr(402)). CRNK expression in 3T3-L1 adipocytes inhibited ET-1-mediated F-actin polymerization and translocation of Myc-tagged GLUT4-enhanced green fluorescent protein (EGFP) to the plasma membrane without disrupting insulin action on these processes. These data reveal the tyrosine kinase PYK2 as a required signaling element in the regulation of GLUT4 recycling in 3T3-L1 adipocytes by ET-1, whereas insulin signaling is directed through a different pathway.

Extrahepatic portal vein tear with intraperitoneal hemorrhage during TIPS

Temporary occlusion with an angioplasty balloon can stop intraperitoneal bleeding.

Signaling complexes of the FERM domain-containing protein GRSP1 bound to ARF exchange factor GRP1

GRP1 is a member of a family of proteins that contain a coiled-coil region, a Sec7 homology domain with guanosine nucleotide exchange activity for the ARF GTP-binding proteins, and a pleckstrin homology domain at the C terminus. The pleckstrin homology domain of GRP1 binds phosphatidylinositol (3,4,5) trisphosphate and mediates the translocation of GRP1 to the plasma membrane upon agonist stimulation of PI 3-kinase activity. Using a (32)P-labeled GRP1 probe to screen a mouse brain cDNA expression library, we isolated a cDNA clone encoding a GRP1-binding partner (GRSP1) that exists as two different splice variants in brain and lung. The GRSP1 protein contains a FERM protein interaction domain as well as two coiled coil domains and may therefore function as a scaffolding protein. Mapping experiments revealed that the interaction of GRP1 and GRSP1 occurs through the coiled coil domains in the two proteins. Immunodepletion experiments indicate that virtually all of the endogenous GRSP1 protein exists as a complex with GRP1 in lung. When co-expressed in Chinese hamster ovary cells expressing the human insulin receptor, both proteins display a diffuse, cytoplasmic localization. Acute translocation and co-localization of GRSP1 and GRP1 to ruffles in the plasma membrane was evident after insulin stimulation. These results identify GRSP1 as a novel member of GRP1 signaling complexes that are acutely recruited to plasma membrane ruffles in response to insulin receptor signaling.

Identification of four novel RB1 germline mutations in Korean retinoblastoma patients

To elucidate RB1 germline mutations in Korean retinoblastoma patients, DNA samples from 14 children with bilateral (including three familial cases) and 19 children with unilateral retinoblastoma were analyzed. We found germline mutations in three out of 14 bilateral cases and one out of 19 unilateral cases. There were no germline mutations in the three familial cases. PCR-SSCP from each exon showed bandshifts in four patients which, upon sequencing, were shown to be K616E in exon 19 (c.1846A>G), an AA insertion in exon 7 (c.684-685insAA), R500G in exon 16 (c.1498A>G), and an A insertion in exon 23 (c.2391-2392insA), respectively. Hum Mutat 18:252, 2001.

A novel tumor-associated mucin of gastrointestinal carcinoma

PURPOSE

To identify a new tumor-associated antigen, a monoclonal antibody, SC142, was produced by immunizing mice with a stomach cancer cell line. The tumor specificity of mAb SC142 was studied by immunohistochemical staining, and the biochemical characteristics of this new gastrointestinal tumor-associated antigen were also studied.

METHODS

The expression of SC142-reactive antigen was investigated in various cancers by immunohistochemical staining. The SC142-reactive antigen was characterized by immunoblotting, sodium metaperiodate treatment assay, O-glycanase digestion assay, and lectin binding assay.

RESULTS

The SC142-reactive antigen was highly expressed in 78% of gastric cancers (29/37) and 87% of colon cancers (27/31). No normal colon or stomach tissues remote from the tumor were positive for the antigen. The antibody also reacted with other tumors of epithelial origin such as lung squamous cell cancer (2/4), breast ductal cancer (2/20), bladder transitional cell carcinoma (4/6), and uterine cancer (3/16). Western blot analysis of the antigen revealed glycoprotein(s) which migrated as a smear ranging from the origin of the gel to about the 80 kDa region. The reactivity of this antigen with SC142 was reduced by sodium metaperiodate treatment or O-glycanase digestion, but not by N-glycanase, suggesting that the epitope is an O-glycan. In lectin-binding assay, this antigen reacted only with wheat germ agglutinin but not with Ricinus communis agglutinin, Datura stramonium agglutinin, and Sambucus nigra agglutinin.

CONCLUSIONS

Our findings indicate that the antigen defined by SC142 is a tumor-associated antigen that could differentiate the gastrointestinal cancer cells from the normal cells. Therefore, SC142 may become a valuable tool for the immunohistochemical diagnosis and tumor immunoscintigraphy of the gastrointestinal cancer patients.

G(alpha)11 signaling through ARF6 regulates F-actin mobilization and GLUT4 glucose transporter translocation to the plasma membrane

The action of insulin to recruit the intracellular GLUT4 glucose transporter to the plasma membrane of 3T3-L1 adipocytes is mimicked by endothelin 1, which signals through trimeric G(alpha)q or G(alpha)11 proteins. Here we report that murine G(alpha)11 is most abundant in fat and that expression of the constitutively active form of G(alpha)11 [G(alpha)11(Q209L)] in 3T3-L1 adipocytes causes recruitment of GLUT4 to the plasma membrane and stimulation of 2-deoxyglucose uptake. In contrast to the action of insulin on GLUT4, the effects of endothelin 1 and G(alpha)11 were not inhibited by the phosphatidylinositol 3-kinase inhibitor wortmannin at 100 nM. Signaling by insulin, endothelin 1, or G(alpha)11(Q209L) also mobilized cortical F-actin in cultured adipocytes. Importantly, GLUT4 translocation caused by all three agents was blocked upon disassembly of F-actin by latrunculin B, suggesting that the F-actin polymerization caused by these agents may be required for their effects on GLUT4. Remarkably, expression of a dominant inhibitory form of the actin-regulatory GTPase ARF6 [ARF6(T27N)] in cultured adipocytes selectively inhibited both F-actin formation and GLUT4 translocation in response to endothelin 1 but not insulin. These data indicate that ARF6 is a required downstream element in endothelin 1 signaling through G(alpha)11 to regulate cortical actin and GLUT4 translocation in cultured adipocytes, while insulin action involves different signaling pathways.

Classic Kaposi sarcoma presenting as rapidly growing nodules

Classic Kaposi sarcoma (KS) is a sporadic disease that usually affects persons older than 50 years, with a distinct male predominance. Although classic KS has a protracted, indolent course, there appears to be a rare disseminated fulminant type. This report describes a case of classic KS, presenting as a very rapid enlargement and dissemination of skin lesions, without evidence of human immunodeficiency virus (HIV) infection or involvement of other internal organs.

Phosphorylation of purified recombinant hepatitis B virus-X protein by mitogen-activated protein kinase and protein kinase C in vitro

The recombinant human hepatitis B virus-X protein (rhHBx) has been expressed as inclusion bodies in Escherichia coli and purified. By sequential dialysis of urea, rhHBx was folded into the native structure, which was demonstrated by both the efficacy of its transcriptional activation of the adenovirus major late promoter, fluorescence and circular dichroism (CD) analysis. The increase in CD values at 220 nm and a corresponding blue shift of the intrinsic fluorescence emission confirmed the ability of HBx to refold in lower concentrations of urea to produce the active protein. After purification and renaturation, the rhHBx protein was found to be phosphorylated by protein kinase C (PKC) and mitogen-activated protein kinase (MAPK). In vivo phosphorylation of HBx was also demonstrated. Although PKC and MAPK enhance the HBx phosphorylation in vitro, neither protein kinase A nor caseine kinase II (CKII) phosphorylate HBx protein, though there are possible substrate residues of both kinases in HBx protein. Phosphoamino acid analysis of the total acid hydrolyzed HBx showed that serine residues can be phosphorylated by PKC or MAPK.

Microsatellite instability in double primary cancers of the colorectum and stomach

Little is known about genetic alterations of patients who present multiple primary cancers. We hypothesized that microsatellite instability (MSI) is one of the underlying genetic factors in the development of double primary cancers in colorectal cancer patients. We examined for MSI in 41 colorectal cancer patients who presented with extra-colonic primary cancers consisted of 17 gastric and 24 non-gastric cancers. Coincident MSI+ in tumors of two organs were observed in 3 (17.7%) of 17 patients with colon and stomach cancers and 0 of 24 patients with colon and non-gastric cancers (P =.03). In 17 patients with colon and stomach cancers, 6 (31.6%) of 19 colon cancers and 3 (17.7%) of 17 gastric cancers exhibited MSI+. Among four patients with metachronous colon cancers who were identified within the 41 double primary cancer patients, two patients were associated with the MSI+ phenotype. In summary, the prevalent coincidence of MSI suggests that genetic defect of mismatch repair deficiency may be responsible for a small subset of double primary cancers of the colorectum and stomach.

CD44 is a potential target of amplification within the 11p13 amplicon detected in gastric cancer cell lines

Classical cytogenetic approaches have revealed many of the chromosomal aberrations that may occur in gastric cancers (GC), although few alterations of specific genes have been identified so far. Genes that affect progression of this disease need to be identified if clinicians are to achieve optimal management of patients with GC. As the first step toward the cloning of gene(s) that may be involved in gastric carcinogenesis, we examined 25 GC cell lines for aberrations in DNA copy number to detect chromosomal gains and losses, as well as gene amplifications, by comparative genomic hybridization (CGH). Our CGH study revealed high-level amplifications in chromosomal regions that had been well defined in GC but also in sites that had not, including 3p24, 5p15, 11p11.2-14, 13q34, 15q26, Xp24, and Xq26-28. The minimal common region at 11p13, within the 11p11.2-14 amplicon, harbors the CD44 gene. Northern and Western blot analyses showed that an alternatively spliced form of CD44, with variant exons 8-10 (CD44E), was overexpressed in all cell lines bearing the 11p13 amplicon. However, cell adhesion activity was no greater in these lines than in cell lines without amplifications at the CD44 locus, suggesting that the major property of upregulated CD44 in these cases might be to transduce signals critically associated with growth and proliferation of the tumor cells.

Mutations in fibroblast growth factor receptor 2 and fibroblast growth factor receptor 3 genes associated with human gastric and colorectal cancers

Autosomal dominant disorders of skeletal and cranial development have been linked to fibroblast growth factor receptor (FGFR) 2 and FGFR3. Here we report two identical mutations in FGFR2 that cause craniosynostosis syndromes, Crouzon, Apert, and Pfeiffer in gastric carcinoma. A missense mutation (Ser267Pro) in exon IIIa and a splice site mutation (940-2A-->G) in exon IIIc were detected in gastric cancer patients. Interestingly, these heterozygous somatic mutations are identical to the germinal activating mutations in FGFR2 reported previously in craniosynostosis syndromes. In addition, the two novel mutations of FGFR3 in colorectal carcinomas were identified. All identified mutations occurred at highly conserved sequences, not only in the FGFR family of molecules, but also throughout evolution and clustered in the immunoglobulin-like loop-III domain, highlighting the functional importance of this domain. Our results indicate that FGFR2 and FGFR3, in addition to their potential role in skeletal dysplasias, play an important role in tumorigenesis.

Synthesis and muscarinic activity of 1,2,3,4-tetrahydropyrimidine derivatives

3-Methyl-1,2,3,4-tetrahydropyrimidine-5-carbaldehyde O-substituted oximes 4 and 1-(3-methyl-1,2,3,4-tetrahydropyrimidin-5-yl)ethanone O-substituted oximes 9 have been prepared as bioisosteric congeners of arecoline which is a muscarinic agonist for treatment of Alzheimer's disease. Starting from pyrimidine-5-carbaldehyde 1, formation of the 3-methylpyrimidinium salt and subsequent reduction afforded 1,2,3,4-tetrahydropyrimidine derivatives which were converted into oxalate salts in the interest of purity and stability. Binding affinities of prepared compounds for the cloned human muscarinic M1 receptor (h-M1) were determined by radioligand binding assay using [3H]-N-methylscopolamine (NMS).

Genetic changes of hOGG1 and the activity of oh8Gua glycosylase in colon cancer

oh8Gua glycosylase repairs DNA by removing oh8Gua, a highly mutagenic oxidative DNA adduct. Recently, the gene for human oh8Gua glycosylase (hOGG1) was cloned and several mutational types have been reported. However, the implications of such mutations in human cancer have not been clearly demonstrated. To test the involvement of hOGG1 mutation in colon carcinogenesis, we analysed the genetic changes of hOGG1 and the activity of oh8Gua glycosylase in 15 paired normal and tumorous colon specimens. The activity of antioxidant enzymes (catalase and superoxide dismutase (SOD)) and extent of oxidative cellular damage (oh8Gua and malondialdehyde) were also assessed to compare the oxidative status of normal and tumour tissues. An Arg 154 to His mutation was detected in two tumour samples, but not in the corresponding normal tissues. A Ser 326 to Cys mutation (polymorphism) was found in both the normal and tumour tissues of 3 patients. However, neither the Arg 154 to His mutation nor the polymorphism at codon 326 significantly decreased the oh8Gua glycosylase activity. The mean activity of oh8Gua glycosylase was significantly higher in the tumours than in normal tissues (P=0.022). Antioxidant enzyme activities were decreased (catalase; P=0.004 and SOD; P=0.002), and the extent of oxidative damage correspondingly increased in the tumour tissues (oh8Gua; P=0.007 and malondialdehyde; P=0.046). Although the sample size was limited, these results suggest that the somatic mutation or the polymorphism of hOGG1 is less likely to be involved in colon carcinogenesis. Nevertheless, the greater oxidative DNA damage in the tumour tissues, as a possible result of impaired antioxidant activity, implies an important role for oxygen free-radicals in colon carcinogenesis.

Detection and typing of human papillomavirus in anal epidermoid carcinomas: sequence variation in the E7 gene of human papillomavirus Type 16

INTRODUCTION

Human papillomavirus, particularly Type 16, plays a central role in the development of anogenital squamous-cell carcinomas. A common sequence variation of human papillomavirus Type 16 in cervical cancer cell lines and in cervical cancer tissues from Korean patients was recently reported. The present study was performed to determine the integration type of human papillomavirus DNA in anal epidermoid carcinoma and to identify the common sequence variations in the human papillomavirus Type 16 E7 gene that had been previously reported.

METHODS

Twenty-one formalin-fixed, paraffin-embedded specimens collected from 29 patients with anal epidermoid carcinomas treated at the Seoul National University Hospital over a ten-year period (1989-1998) were investigated. Genomic DNA from the 21 specimens was extracted and analyzed using the polymerase chain reaction with a general primer and a type-specific primer for human papillomavirus Types 16 and 18. Direct sequencing was performed. As a control, 13 normal anal epithelia available from these patients were microdissected. As another control, 21 hemorrhoidal squamous epithelia obtained from a demographically adjusted group were also analyzed.

RESULTS

Human papillomavirus Type 16 DNA was present in all 21 anal epidermoid carcinomas. All controls were negative for human papillomavirus DNA. Sequence analysis revealed that 57 percent (12/21) specimens showed two types of sequence variation in the E7 gene. One variant with a single nucleotide change at position 647 (amino acid 29, AAT-->AGT, asparagine to serine) was found in 38 percent (8/21) of the samples. This variant has been detected in cervical cancers from Korean patients: 19 (39 percent) of 49 cervical cancer tissues and 6 (50 percent) of 12 cervical cancer cell lines. Another single nucleotide change at position 645 (amino acid 28, TTA-->TTC, leucine to phenylalanine) was found in 19 percent (4/21) of the samples. These two variants exhibit a change of amino acid affecting the critical sites for Rb binding.

CONCLUSION

Human papillomavirus Type 16 was found to be present in all 21 anal epidermoid carcinomas. Furthermore, in the Korean population, the most common sequence variant found in cervical

Patient preference between visible light-cured and heat-cured acrylic splints

PURPOSE

To compare the advantages/disadvantages concerning patient subjective preferences of splints made with heat-cured acrylic (Splint Resin Polymer) or visible light-cured material.

MATERIAL AND METHODS

A questionnaire was developed assessing: comfort, stability, fit, taste, occlusal contacts, lip seal, smoothness, hygiene, color stability, stain resistance, salivation level, gingival irritation, bulkiness and odor. 10 patients already treatment planned to receive splints, were chosen at random from the dental school. Splints made from the two types of materials were delivered to each patient to be used for 3 wks. The material to initially be used was chosen at random and the questionnaire was answered after each 3-wk period.

RESULTS

The MacNemar's Chi-square test revealed that there was no statistical difference in patient preference between the two splint materials.

CD44 is a potential target of amplification within the 11p13 amplicon detected in gastric cancer cell lines

Classical cytogenetic approaches have revealed many of the chromosomal aberrations that may occur in gastric cancers (GC), although few alterations of specific genes have been identified so far. Genes that affect progression of this disease need to be identified if clinicians are to achieve optimal management of patients with GC. As the first step toward the cloning of gene(s) that may be involved in gastric carcinogenesis, we examined 25 GC cell lines for aberrations in DNA copy number to detect chromosomal gains and losses, as well as gene amplifications, by comparative genomic hybridization (CGH). Our CGH study revealed high-level amplifications in chromosomal regions that had been well defined in GC but also in sites that had not, including 3p24, 5p15, 11p11.2-14, 13q34, 15q26, Xp24, and Xq26-28. The minimal common region at 11p13, within the 11p11.2-14 amplicon, harbors the CD44 gene. Northern and Western blot analyses showed that an alternatively spliced form of CD44, with variant exons 8-10 (CD44E), was overexpressed in all cell lines bearing the 11p13 amplicon. However, cell adhesion activity was no greater in these lines than in cell lines without amplifications at the CD44 locus, suggesting that the major property of upregulated CD44 in these cases might be to transduce signals critically associated with growth and proliferation of the tumor cells.

Histoclinical analysis of early colorectal cancer

To evaluate the clinicopathologic characteristics of early colorectal cancer (ECC), histopathologic and clinical features of 90 ECC patients who underwent surgical resection (not including the endoscopic polypectomized cases) and 1704 patients with advanced colorectal cancer were analyzed. Smaller size, better histologic differentiation, less lymph node (LN) metastasis, and better clinical outcome were observed in those with ECC than in patients with more advanced lesions. LN metastasis was found in 5 patients with ECC among the 56 patients who underwent bowel resection (8.9%). Tumors with LN metastasis were more frequently associated with deep submucosal invasion, absence of an adenomatous component within the tumor, sessile configuration, and lymphovascular invasion. Tumors showing deep submucosal layer invasion were associated with a more unfavorable histologic grade, lymphovascular invasion, LN metastasis, sessile morphology, and absence of an adenomatous component within the tumor. Recurrence was observed in two patients who underwent local excision for their submucosal cancer. One of the patients was salvaged after bowel resection, but one patient died of distant metastasis. From our data analysis and literature review, extensive submucosal invasion, lymphovascular invasion, sessile configuration, and tumors with no adenomatous component should be considered high risk factors for LN metastasis and recurrence after limited therapy.

Methylation of the CDH1 promoter as the second genetic hit in hereditary diffuse gastric cancer

Aberrant promoter methylation and the associated loss of gene expression is a common accompaniment of human cancers. Nonetheless, it has been challenging to demonstrate in any given tumour that methylation of a specific gene was causal and not consequent to malignant transformation. In this regard, our attention was drawn to the genesis of gastric cancers in individuals with hereditary diffuse gastric cancer (HDGC). These individuals harbour germline mutations in the gene encoding E-cadherin, CDH1, but their cancers have consistently demonstrated absence of loss of heterozygosity at the CDH1 locus. These findings suggested the hypothesis that CDH1 promoter methylation might function as the 'second genetic hit' in the genesis of these cancers.

Genetic alterations in gastric cancer cell lines and their original tissues

To investigate the genetic changes that occur during establishment of gastric cancer cell lines, 4 gastric cancer cell lines and their original tumor tissues were examined for microsatellite instability (MSI), loss of heterozygosity (LOH), and p53 mutation. MSI status did not change during the establishment, though the cell lines gained frameshift mutation in some of the genes with polytract coding sequences. There was no difference in p53 mutation between the cell lines and the original tumors. The frequency of LOH was similar between the cell lines and each original tumor, in the range 30.8% to 85.7%. The difference in the LOH results between the cell lines and the original tumors was not greater than the difference between the different areas of the original tumors. The above results suggested that most of the genetic alterations, such as MSI, LOH, and p53 gene mutation, were sustained during the establishment of gastric cancer cell lines. Minor genetic differences between original tumor tissues and cancer cell lines could be explained as a tumor heterogeneity because separate areas of the original tumor tissues manifest similar variations.