Sequential multimodal treatments with chemotherapy and surgery for advanced soft tissue sarcoma may be associated with better survival than chemotherapy.

BACKGROUND: In patients with advanced soft tissue sarcoma (STS), surgery had been reported to be associated with superior overall survival (OS). Chemotherapy details for such patients were less reported, and whether multimodal treatment with surgery and chemotherapy provides extra survival benefit remains unclear. METHODS: We retrospectively reviewed patients with newly diagnosed advanced STS treated at National Taiwan University Hospital from January 1, 2011, to December 31, 2017. OS was calculated from the day of diagnosis of advanced STS to the day of death or last follow-up. Baseline patient characteristics and details regarding surgery and chemotherapy were recorded. RESULTS: A total of 545 patients were diagnosed with STS from 2011 to 2017, of which 226 patients had advanced STS. The median age was 54.7 years, and 54% of patients were women. Approximately 38% of patients with advanced STS underwent surgery and exhibited a trend of longer OS compared with who did not (median = 18.6 vs. 11.9 months, p = 0.083). In the chemotherapy subgroup, the benefit of surgery was more prominent (median = 21.9 vs. 16.5 months, p = 0.037). Patients who received chemotherapy prior to surgery exhibited numerically longer OS than those who underwent surgery first (median = 33.9 vs. 18.3 months, p = 0.155). After adjusting other clinical factors, chemotherapy remained an independent factor associated with favourable OS. CONCLUSION: Surgery may be more beneficial for the patients who receive chemotherapy. Our results support evaluation of sequential multimodal treatments strategy including surgery and chemotherapy in patients with advanced STS.

The synergistic effects of quercetin-containing 3D-printed mesoporous calcium silicate/calcium sulfate/poly-ε-caprolactone scaffolds for the promotion of osteogenesis in mesenchymal stem cells.

BACKGROUND/PURPOSE: Several growth factors were proven to be effective in the treatment of bone defects and fractures and thus have great potential for bone regeneration applications. However, it needs low-temperature storage and transportation. This study aimed to investigate the herbal extract quercetin, a candidate for natural flavonoid compounds that have been reported to be involved in regulating inflammation and improving immunity and health. METHODS: In this study, we prepared quercetin (Q)/mesoporous calcium silicate calcium sulfate (MSCS)/polycaprolactone (PCL) composite scaffolds using the 3D printing technique, where we immersed it in simulated body fluid (SBF) solution and soaked it for up to 60 days. The characteristics of quercetin scaffold were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), immunofluorescence, and Alizarin Red S staining. RESULTS: We found precipitation of apatite on the surface of the scaffold. The in vitro results for cell proliferation, cytotoxicity, and immunofluorescence staining revealed that Wharton's jelly mesenchymal stem cells (WJMSCs) with a 2% quercetin (Q2) scaffold were significantly higher in number than with 1% quercetin (Q1) and MSCS scaffolds. The phalloidin staining of cell skeletons on the surface of Q2 revealed powerful cell-to-cell adhesion and high expression of green fluorescence. The Q2 scaffold also had the highest calcium deposit levels based on Alizarin Red S staining in all scaffolds. This indicated that quercetin was able to induce cell growth and mitosis, echoing the previous preliminary results. CONCLUSION: Our initial results indicate that this natural herbal extract can be a good bone-based gene substitution for bone regeneration.

Comparing image qualities of dental cone-beam computed tomography with different scanning parameters for detecting root canals.

BACKGROUND/PURPOSE: Cone-beam computed tomography (CBCT) is a useful device in creating 3-dimensional images in the examining area of dentistry and is one of the most common clinical methods in detecting second mesiobuccal (MB2) canals in maxillary molars. The aim of this in vitro study was to compare the image quality of the small field of view (FOV) CBCT with different rotation arcs and scanning speeds in the use of detecting root canals. METHODS: A dentate human skull was scanned in Morita 3D Accuitomo 170 with 4 × 4 cm FOV under 5 mA and 90 kVp. Two different rotation arcs (360° and 180°) and three different scanning modes (slow-speed mode, standard mode and high-speed mode) combined into six different groups. Five different levels of axial sections were selected from each group. Five endodontic specialists rated the image quality by focusing on the sharpness of the MB2 canal of the upper right first molar and the surrounding structures. RESULTS: Despite the rotation arcs, all the observers gave excellent ratings to images taken with slow-speed mode. The high-speed mode taken with 360° and 180° got the second lowest and the lowest ratings, respectively. Under the same scanning speed, the rotation arc did not have a significant difference in image quality. CONCLUSION: Slow-speed mode is inevitable in maintaining adequate image quality during taking CBCT. However, endodontists can use the half rotation mode to significantly reduce radiation dose, exposure time, and still maintain sufficient image quality for root canal anatomy assessment.

Effects of bone morphogenic protein-2 loaded on the 3D-printed MesoCS scaffolds.

BACKGROUND/PURPOSE: The mesoporous calcium silicate (MesoCS) 3D-printed scaffold show excellent bioactivity and can enhance the bone-like apatite formation. The purpose of this study aims to consider the effects of the different loading methods on the novel grafting materials which composed of bone morphogenetic protein-2 (BMP-2) loaded MesoCS scaffold by employing 3D-printing technique. METHODS: The MesoCS scaffold were fabricated by fused deposition modeling. In this study, there are two methods of loading BMP-2: (1) the pre-loading (PL) method by mixing MesoCS and BMP-2 as a raw material for a 3D-printer, and (2) the direct-loading (DL) method by soaking the 3D-printed MesoCS scaffold in a BMP-2 solution. The characteristics of MesoCS scaffold were examined by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Their physical properties, biocompatibility, and osteogenic-related ability were also evaluated. RESULTS: The 3D MesoCS/PCL scaffolds showed excellent biocompatibility and physical properties. After soaking in simulated body fluid, the bone-like apatite layer of the PL and DL groups could be formed. In addition, the DL group released fifty percent more than the PL group at the end of the first day and PL showed a sustained release profile after 2 weeks. CONCLUSION: The 3D MesoCS/PCL porous scaffolds were successfully fabricated via a 3D printing system and were tested in vitro and were found to show good cellular activity for cell behavior although the PL method was not favorable for clinical application in relation with the preservation of BMP-2. With regards to different growth factor loading methods, this study demonstrated that PL of BMP-2 into MesoCS prior to printing will result in a more sustained drug release pattern as compared to traditional methods of scaffolds directly immersed with BMP-2.

Clozapine protects bone mineral density in female patients with schizophrenia.

Decreased bone mineral density (BMD) is common in patients with schizophrenia; however, the pathogenesis is unclear. Different classes of antipsychotic agents may affect BMD. This study systemically examined the effects of clozapine vs. other antipsychotics, and several hormonal and metabolic factors that may contribute to BMD in female patients with schizophrenia, who are more vulnerable than males. Forty-eight women with schizophrenia, treated with long-term antipsychotics of the prototype prolactin-sparing (PS) antipsychotic agent clozapine vs. prolactin-raising (PR) antipsychotics were enrolled. They were matched for demographic and clinical characteristics. Various factors, including blood levels of prolactin and sex hormones, psychopathological symptoms, global assessment of functioning, physical activity, and menopausal status, were determined to explore their contribution to low BMD (LBMD), defined as a dual-energy X-ray absorptiometer (DEXA) T score <-1. Overall, women receiving clozapine have better bone density than women receiving PR antipsychotics. Compared to PR antipsychotics, PS clozapine therapy is a protective factor (odds ratio 28.2, 95% confidence interval 2.37-336.10, p=0.008) for LBMD. Predictors for higher bone density in the clozapine group included higher clozapine dose (p<0.001), younger age (p<0.001), and higher thyroid-stimulating hormone level (p<0.001); in the PR group, higher body mass index (p=0.003) and lower alkaline phosphatase level (p=0.007) were associated with LBMD. This study suggests that clozapine treatment is beneficial for BMD compared to PR antipsychotic treatment in women with chronic schizophrenia, and clozapine's bone-density protecting effect is dose-related.

Incorporation of Calcium Sulfate Dihydrate into a Mesoporous Calcium Silicate/Poly-ε-Caprolactone Scaffold to Regulate the Release of Bone Morphogenetic Protein-2 and Accelerate Bone Regeneration.

Tissue engineering and scaffolds play an important role in tissue regeneration by supporting cell adhesion, proliferation, and differentiation. The design of a scaffold is critical in determining its feasibility, and it is critical to note that each tissue is unique in terms of its morphology and composition. However, calcium-silicate-based scaffolds are undegradable, which severely limits their application in bone regeneration. In this study, we developed a biodegradable mesoporous calcium silicate (MS)/calcium sulfate (CS)/poly-ε-caprolactone (PCL) composite and fabricated a composite scaffold with 3D printing technologies. In addition, we were able to load bone morphogenetic protein-2 (BMP-2) into MS powder via a one-step immersion procedure. The results demonstrated that the MS/CS scaffold gradually degraded within 3 months. More importantly, the scaffold exhibited a gradual release of BMP-2 throughout the test period. The adhesion and proliferation of human dental pulp stem cells on the MS/CS/BMP-2 (MS/CS/B) scaffold were significantly greater than that on the MS/CS scaffold. It was also found that cells cultured on the MS/CS/B scaffold had significantly higher levels of alkaline phosphatase activity and angiogenic-related protein expression. The MS/CS/B scaffold promoted the growth of new blood vessels and bone regeneration within 4 weeks of implantation in rabbits with induced critical-sized femoral defects. Therefore, it is hypothesized that the 3D-printed MS/CS/B scaffold can act both as a conventional BMP-2 delivery system and as an ideal osteoinductive biomaterial for bone regeneration.

A randomized, double-blind comparison of risperidone versus low-dose risperidone plus low-dose haloperidol in treating schizophrenia.

Monotherapy is recommended for schizophrenia treatment, but the risk-benefit issue of antipsychotic drug combination (except for clozapine) remains unclear. Risperidone, an atypical antipsychotic drug, has a lower incidence of extrapyramidal syndrome but higher risks of prolactinemia and metabolic syndrome than haloperidol, a typical agent. This study compared efficacy and safety of risperidone monotherapy versus low-dose risperidone plus low-dose haloperidol in schizophrenia. In this 6-week, double-blind study, patients were randomized to the combination group (2-mg/d risperidone plus 2-mg/d haloperidol, n = 46) or the monotherapy group (4-mg/d risperidone, n = 42). Efficacy assessments included Clinical Global Impression-Severity, Positive and Negative Syndrome Scale and subscales, Calgary Depression Scale, Global Assessment of Functioning, and Medical Outcomes Study Short-Form 36. Safety was rigorously monitored. Response was defined as 30% reduction in the Positive and Negative Syndrome Scale total score. The 2 treatment groups were similar in (1) demographic and clinical characteristics at baseline, (2) response rate, and (3) improvement in various psychopathological measures and quality of life at end point. The monotherapy group had a higher increase in prolactin levels (P = 0.04) and Simpson-Angus Scale scores (P = 0.04) and a higher percentage of biperiden use (P = 0.045). There were no significant between-group difference in changes in weight, vital signs, corrected QT interval, liver/renal function, fasting glucose level, and lipid profiles. The findings suggest that risperidone monotherapy may yield higher prolactin levels than a combination of low-dose risperidone plus low-dose haloperidol. The 2 treatment groups are similar in efficacy, life quality, and other safety profiles. Future long-term studies are warranted.

Genetic Effects of DISC1 and G72 (DAOA) on Visual Learning of Patients with Schizophrenia.

BACKGROUND: Visual learning plays an important role in general populations and patients with schizophrenia. Genetic influences on visual learning remain unknown. Two functional single nucleotide polymorphisms (SNPs), Ser704Cys of the DISC1 gene and M24 (rs1421292) of the G72 gene, are strongly associated with pathogenesis and pathophysiology of schizophrenia. This study examined these two SNPs' effects on visual learning in schizophrenia patients. METHODS: Two hundred seventy-one patients (mean age, 37.0 years [SD = 9.3]; 159 men) with chronic schizophrenia were genotyped for the DISC1 Ser704Cys and G72 M24 SNPs and assessed for visual learning with Visual Reproduction II (delayed reproduction) of Wechsler Memory Scale - III (WMS-III). For comparison, verbal learning (using Word list II of WMS-III) and attention (by Continuous Performance Test) were also measured. RESULTS: The DISC1 Ser carriers excelled DISC1 Cys/Cys homozygotes in visual learning (p=0.004, effect size: 0.43), but not in other cognitive functions. G72 M24 A-allele carriers and G72 M24 T/T homozygotes performed similarly (effect size: 0.07). In SNP-SNP interaction analysis, the patients with Ser carrier_T/T had better visual learning than those with Cys/Cys_T/T (p=0.004, effect size: 0.70) and those with Cys/Cys_A-allele carrier (p=0.003, effect size: 0.65). Education had a positive effect (p=0.007), while negative symptoms had a negative effect (p<0.001) on visual learning. CONCLUSION: The findings suggest that genetic variations in DISC1 Ser704Cys and G72 M24 affect visual learning in schizophrenia patients. The effect sizes of SNP-SNP interaction surpassed the sum (0.50) of effect sizes from two individual genes, suggesting synergistic DISC1-G72 interaction.

Enhanced Capability of Bone Morphogenetic Protein 2-loaded Mesoporous Calcium Silicate Scaffolds to Induce Odontogenic Differentiation of Human Dental Pulp Cells.

INTRODUCTION: Calcium silicate bioceramics have been broadly used as reparative or grafting materials with good bioactivity and biocompatibility in dental application. It has been shown that applying a mesoporous process to calcium silicate gives it great potential as a controlled drug delivery system. METHODS: The aim of this study was to investigate a novel osteoinductive scaffold by loading bone morphogenetic protein 2 (BMP-2) to mesoporous calcium silicate (MesoCS) and fabricating it as 3-dimensional scaffolds using fused deposition modeling combined with polycaprolactone. RESULTS: The MesoCS/BMP-2 scaffold showed similar patterns to that of a calcium silicate scaffold in releasing calcium and silicon ions in a simulated body fluid (SBF) immersion test for 7 days, but BMP-2 continued releasing from the MesoCS/BMP-2 scaffold significantly more than the CS scaffold from 48 hours to 7 days. Adhesion and proliferation of human dental pulp cells cultured on a MesoCS/BMP-2 scaffold were also more significant than scaffolds without BMP-2 or mesoporous as well as the results of the test on alkaline phosphatase activity. CONCLUSIONS: The results support that the novel 3-dimensional-printed MesoCS scaffold performed well as BMP-2 delivery system and would be an ideal odontoinductive biomaterial in regenerative endodontics.

Differential expression of claudin-4 between intestinal and diffuse-type gastric cancer.

Our previous microarray analysis of gastric cancer found that claudin-4 was differentially expressed between intestinal-type gastric cancer (IGC) and diffuse-type gastric cancer (DGC). Claudin-4 is a member of a large family of transmembrane proteins, claudins, essential in the formation and maintenance of tight junctions. To explore the roles of claudin-4 in the two histologically distinct types of gastric cancer, we selected 45 IGC and 48 DGC cases and then analyzed the expression of the protein using immunohistochemistry. We found that the overexpression of claudin-4 was greater in IGC than in DGC. A trend was observed between the overexpression of claudin-4 and lymph node metastasis, however, this association was not statistically significant. The results showed that the expression of claudin-4 was lower in DGC. Possibly it played a role in determining the diffuse phenotype and loose cohesion of cells in DGC in a similar manner as E-cadherin.

Benthic fluxes of dissolved organic carbon from gas hydrate sediments in the northern South China Sea.

Hydrocarbon vents have recently been reported to contribute considerable amounts of dissolved organic carbon (DOC) to the oceans. Many such hydrocarbon vents widely exist in the northern South China Sea (NSCS). To investigate if these hydrocarbon vent sites release DOC, we used a real-time video multiple-corer to collect bottom seawater and surface sediments at vent sites. We analyzed concentrations of DOC in these samples and estimated DOC fluxes. Elevated DOC concentrations in the porewaters were found at some sites suggesting that DOC may come from these hydrocarbon vents. Benthic fluxes of DOC from these sediments were 28 to 1264 µmol m(-2 )d(-1) (on average ~321 µmol m(-2 )d(-1)) which are several times higher than most DOC fluxes in coastal and continental margin sediments. The results demonstrate that the real-time video multiple-corer can precisely collect samples at vent sites. The estimated benthic DOC flux from the methane venting sites (8.6 × 10(6 )mol y(-1)), is 24% of the DOC discharge from the Pearl River to the South China Sea, indicating that these sediments make an important contribution to the DOC in deep waters.

A highly sensitive underwater video system for use in turbid aquaculture ponds.

The turbid, low-light waters characteristic of aquaculture ponds have made it difficult or impossible for previous video cameras to provide clear imagery of the ponds' benthic habitat. We developed a highly sensitive, underwater video system (UVS) for this particular application and tested it in shrimp ponds having turbidities typical of those in southern Taiwan. The system's high-quality video stream and images, together with its camera capacity (up to nine cameras), permit in situ observations of shrimp feeding behavior, shrimp size and internal anatomy, and organic matter residues on pond sediments. The UVS can operate continuously and be focused remotely, a convenience to shrimp farmers. The observations possible with the UVS provide aquaculturists with information critical to provision of feed with minimal waste; determining whether the accumulation of organic-matter residues dictates exchange of pond water; and management decisions concerning shrimp health.

Human 8-oxoguanine DNA glycosylase 1 mRNA expression as an oxidative stress exposure biomarker of cooking oil fumes.

Epidemiological studies have indicated that the exposure to carcinogenic components formed during the cooking of food might be associated with lung cancer risk of Chinese women. Previous studies have confirmed that cooking oil fumes from frying fish (COF) contained relatively high amount of benzo[a]pyrene, 2-methyl-3,8-dimethylimidazo[4,5-f] qunoxaline, benzene, and 1,3-butadiene, reported in fumes from heated soybean oil. Thus, we consider that oxidative stress induced by COF may play a role in lung cancer development among Chinese women. To verify whether the oxidative DNA damage was induced by COF, high-performance liquid chromatography (HPLC) analysis data showed that the levels of 8-hydroxydeoxyguanine (8-OH dG) were increased in a dose-dependent manner when calf thymus DNA reacted with various concentrations of COF. Since human 8-oxoguanine DNA glycosylase 1 (hOGG1) was a repair enzyme for removing 8- OH dG from damaged DNA, we hypothesized that hOGG1 mRNA may be used to assess the risk of oxidative damage induced by the exposure of COF. The results from reverse-transcription polymerase chain reaction showed that the hOGG1 mRNA expression was induced by hydrogen peroxide (H2O2) and COF in human lung adenocarcinoma CL-3 cells. To elucidate whether hOGG1 mRNA expression was an exposure biomarker of COF, a cross-sectional study of 238 subjects including 94 professional cooks, 43 housewives, and 101 COF-nonexposed control subjects was conducted. The hOGG1 mRNA expression frequencies of COF-exposed cooks (27 of 94, 28.7%) and housewives (6 of 43, 14%) were significantly higher than those of control subjects (4 of 101, 4%). After adjusting for age, sex, and smoking and drinking status, the odds risks (ORs) of housewives versus control and cooks versus control were 3.94 (95% confidence interval [CI] = 0.95-16.62) and 10.12 (95% CI = 2.83-36.15), respectively. These results indicated that hOGG1 may be adequate to act as an exposure biomarker to assess the oxidative DNA damage induced by COF. This also suggests that oxidative stress induced by COF may play a role in lung cancer development among Chinese women.

Impaired impulse control is associated with a 5-HT2A receptor polymorphism in schizophrenia.

The impact of the serotonin2a (5-HT2A) receptor gene on the pathophysiology of schizophrenia is inconclusive despite accumulating evidence implicating the 5-HT2A receptor. To simplify the complexity of genetic analysis, we used an endophenotype approach. The relationship between Continuous Performance Test (CPT) performance and 5-HT2A receptor gene variance was examined. Both patients with schizophrenia (n=255) and healthy volunteers (n=380) were recruited. All were genotyped for the -1438A/G polymorphism and assessed with the CPT. The Positive and Negative Syndrome Scale and the Scale for the Assessment of Negative Symptoms were used to evaluate patients' clinical symptoms. The distribution of the 5-HT2A genotypes between patients and healthy controls was similar. Impulse control in schizophrenic patients, assessed with the false-alarm rate of the CPT, differed significantly between those with different 5-HT2A genotypes. We hypothesize that the 5-HT2A receptor gene is a modifier gene of schizophrenia and suggest that additional studies are warranted.

Inhibition of glycine transporter-I as a novel mechanism for the treatment of depression.

BACKGROUND: Antidepressants, aiming at monoaminergic neurotransmission, exhibit delayed onset of action, limited efficacy, and poor compliance. Glutamatergic neurotransmission is involved in depression. However, it is unclear whether enhancement of the N-methyl-D-aspartate (NMDA) subtype glutamate receptor can be a treatment for depression. METHODS: We studied sarcosine, a glycine transporter-I inhibitor that potentiates NMDA function, in animal models and in depressed patients. We investigated its effects in forced swim test, tail suspension test, elevated plus maze test, novelty-suppressed feeding test, and chronic unpredictable stress test in rats and conducted a 6-week randomized, double-blinded, citalopram-controlled trial in 40 patients with major depressive disorder. Clinical efficacy and side effects were assessed biweekly, with the main outcomes of Hamilton Depression Rating Scale, Global Assessment of Function, and remission rate. The time course of response and dropout rates was also compared. RESULTS: Sarcosine decreased immobility in the forced swim test and tail suspension test, reduced the latency to feed in the novelty-suppressed feeding test, and reversed behavioral deficits caused by chronic unpredictable stress test, which are characteristics for an antidepressant. In the clinical study, sarcosine substantially improved scores of Hamilton Depression Rating Scale, Clinical Global Impression, and Global Assessment of Function more than citalopram treatment. Sarcosine-treated patients were much more likely and quicker to remit and less likely to drop out. Sarcosine was well tolerated without significant side effects. CONCLUSIONS: Our preliminary findings suggest that enhancing NMDA function can improve depression-like behaviors in rodent models and in human depression. Establishment of glycine transporter-I inhibition as a novel treatment for depression waits for confirmation by further proof-of-principle studies.

MET and AKT genetic influence on facial emotion perception.

BACKGROUND: Facial emotion perception is a major social skill, but its molecular signal pathway remains unclear. The MET/AKT cascade affects neurodevelopment in general populations and face recognition in patients with autism. This study explores the possible role of MET/AKT cascade in facial emotion perception. METHODS: One hundred and eighty two unrelated healthy volunteers (82 men and 100 women) were recruited. Four single nucleotide polymorphisms (SNP) of MET (rs2237717, rs41735, rs42336, and rs1858830) and AKT rs1130233 were genotyped and tested for their effects on facial emotion perception. Facial emotion perception was assessed by the face task of Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). Thorough neurocognitive functions were also assessed. RESULTS: Regarding MET rs2237717, individuals with the CT genotype performed better in facial emotion perception than those with TT (p = 0.016 by ANOVA, 0.018 by general linear regression model [GLM] to control for age, gender, and education duration), and showed no difference with those with CC. Carriers with the most common MET CGA haplotype (frequency = 50.5%) performed better than non-carriers of CGA in facial emotion perception (p = 0.018, df = 1, F = 5.69, p = 0.009 by GLM). In MET rs2237717/AKT rs1130233 interaction, the C carrier/G carrier group showed better facial emotion perception than those with the TT/AA genotype (p = 0.035 by ANOVA, 0.015 by GLM), even when neurocognitive functions were controlled (p = 0.046 by GLM). CONCLUSIONS: To our knowledge, this is the first study to suggest that genetic factors can affect performance of facial emotion perception. The findings indicate that MET variances and MET/AKT interaction may affect facial emotion perception, implicating that the MET/AKT cascade plays a significant role in facial emotion perception. Further replication studies are needed.

Methylation of RASSF1A, RASSF2A, and HIN-1 is associated with poor outcome after radiotherapy, but not surgery, in oral squamous cell carcinoma.

PURPOSE: Radiotherapy is the standard adjuvant treatment for oral squamous cell carcinoma (OSCC). The Ras/PI3K/AKT pathway is the major mechanism associated with radioresistance. To evaluate the potential significance on the outcome of radiotherapy in OSCC of the Ras/PI3K/AKT pathway with respect to methylation of negative regulators, we examined the methylation status of genes known to be involved in Ras/PI3K/AKT pathway and aberrantly methylated in human cancers together with the mutation status of K-ras/H-ras. EXPERIMENTAL DESIGN: PCR--denaturing high-performance liquid chromatography was used to examine the methylation status of the RASSF1A, RASSF2A, PTEN, and HIN-1 genes, and PCR-RFLP was used to determine the mutation status of K-ras/H-ras in 482 OSCCs. Associations between mutation, methylation, clinicopathologic parameters, and outcome were evaluated. RESULTS: The frequencies of K-ras/H-ras mutation and promoter methylation of the RASSF1A, RASSF2A, PTEN, and HIN-1 genes were 6.6%, 22.4%, 27.8%, 1.2%, and 7.3%, respectively. A combination of RASSF1A and RASSF2A methylation was found to be significantly associated with poor disease-free survival (DFS). Furthermore, a gene dosage effect of the activated Ras/PI3K/AKT signal on DFS was observed in patients treated with radiotherapy after surgery but not in patients treated with surgery alone. The Ras/PI3K/AKT pathway was activated in 140 primary OSCCs among 286 patients treated with radiotherapy after surgery and methylation of RASSF1A/RASSF2A (75.7%) was the most common mechanism. CONCLUSION: Our study indicates that epigenetic silencing of tumor suppressor genes involved in the Ras/PI3K/AKT pathway plays an important role in OSCC radioresistance and this provides a rationale for exploring novel treatment strategies.

Expression of matrix metalloproteinases MMP-2 and MMP-9 in gastric cancer and their relation to claudin-4 expression.

Matrix metalloproteinases (MMPs) MMP-2 and MMP-9 can degrade type IV collagen of extracellular matrix and basal membranes. Claudin-4 is a member of a large family of transmembrane proteins, claudins, essential in the formation and maintenance of tight junctions. Claudin-4 has been shown to activate MMP-2, indicating that claudin-mediated increased cancer cell invasion might be mediated through the activation of MMP proteins. To explore the roles of MMP-2, MMP-9 and claudin-4 in gastric cancer, we selected 88 cases and then analyzed the expression of these proteins using immunohistochemistry. We found that all of MMP-2, MMP-9 and claudin-4 expressions were significantly higher in intestinal-type than in diffuse-type gastric cancer. On further analysis, testing the relationship between MMP-2 and MMP-9 expression with claudin-4 expression, claudin-4 expression was significantly associated with MMP-9 expression, but not with MMP-2 expression. The results showed that MMP-2, MMP-9 and claudin-4 expression may be phenotypic features, distinguishing intestinal-type and diffuse-type gastric cancer. Possibly, claudin-4 played a role in determining MMP-9 activity which favored intestinal-type gastric cancer to distal metastasis.