Real-world NUDT15 genotyping and thiopurine treatment optimization in inflammatory bowel disease: a multicenter study

BACKGROUND

This study evaluated the effectiveness of NUDT15 codon 139 genotyping in optimizing thiopurine treatment for inflammatory bowel disease (IBD) in Japan, using real-world data, and aimed to establish genotype-based treatment strategies.

METHODS

A retrospective analysis of 4628 IBD patients who underwent NUDT15 codon 139 genotyping was conducted. This study assessed the purpose of the genotyping test and subsequent prescriptions following the obtained results. Outcomes were compared between the Genotyping group (thiopurine with genotyping test) and Non-genotyping group (thiopurine without genotyping test). Risk factors for adverse events (AEs) were analyzed by genotype and prior genotyping status.

RESULTS

Genotyping test for medical purposes showed no significant difference in thiopurine induction rates between Arg/Arg and Arg/Cys genotypes, but nine Arg/Cys patients opted out of thiopurine treatment. In the Genotyping group, Arg/Arg patients received higher initial doses than the Non-genotyping group, while Arg/Cys patients received lower ones (median 25 mg/day). Fewer AEs occurred in the Genotyping group because of their lower incidence in Arg/Cys cases. Starting with < 25 mg/day of AZA reduced AEs in Arg/Cys patients, while Arg/Arg patients had better retention rates when maintaining ≥ 75 mg AZA. Nausea and liver injury correlated with thiopurine formulation but not dosage. pH-dependent mesalamine reduced leukopenia risk in mesalamine users.

CONCLUSIONS

NUDT15 codon 139 genotyping effectively reduces thiopurine-induced AEs and improves treatment retention rates in IBD patients after genotype-based dose adjustments. This study provides data-driven treatment strategies based on genotype and identifies risk factors for specific AEs, contributing to a refined thiopurine treatment approach.

Real-world efficacy and safety of tofacitinib treatment in Asian patients with ulcerative colitis

BACKGROUND

Real-world data on tofacitinib (TOF) covering a period of more than 1 year for a sufficient number of Asian patients with ulcerative colitis (UC) are scarce.

AIM

To investigate the long-term efficacy and safety of TOF treatment for UC, including clinical issues.

METHODS

We performed a retrospective single-center observational analysis of 111 UC patients administered TOF at Hyogo Medical University as a tertiary inflammatory bowel disease center. All consecutive UC patients who received TOF between May 2018 and February 2020 were enrolled. Patients were followed up until August 2020. The primary outcome was the clinical response rate at week 8. Secondary outcomes included clinical remission at week 8, cumulative persistence rate of TOF administration, colectomy-free survival, relapse after tapering of TOF and predictors of clinical response at week 8 and week 48.

RESULTS

The clinical response and remission rates were 66.3% and 50.5% at week 8, and 47.1% and 43.5% at week 48, respectively. The overall cumulative clinical remission rate was 61.7% at week 48 and history of anti-tumor necrosis factor-alpha (TNF-α) agents use had no influence (P = 0.25). The cumulative TOF persistence rate at week 48 was significantly lower in patients without clinical remission than in those with remission at week 8 (30.9% vs 88.1%; P < 0.001). Baseline partial Mayo Score was significantly lower in responders vs non-responders at week 8 (odds ratio: 0.61, 95% confidence interval: 0.45-0.82, P = 0.001). Relapse occurred in 45.7% of patients after TOF tapering, and 85.7% of patients responded within 4 wk after re-increase. All 6 patients with herpes zoster (HZ) developed the infection after achieving remission by TOF.

CONCLUSION

TOF was more effective in UC patients with mild activity at baseline and its efficacy was not affected by previous treatment with anti-TNF-α agents. Most relapsed patients responded again after re-increase of TOF and nearly half relapsed after tapering off TOF. Special attention is needed for tapering and HZ.

Treatment strategy for successful conversion surgery in clinical stage IVB gastric cancer

INTRODUCTION

Recent advances in chemotherapy have resulted in successful conversion surgery (CS) for clinical stage (cStage) IVB gastric cancer (GC). This study aimed to evaluate the success rate of CS in clinical practice and determine optimal treatment strategies.

METHODS

Totally, 166 patients with cStage IVB gastric and gastroesophageal junction adenocarcinoma, who underwent chemotherapy at Hyogo Medical University Hospital between January 2017 and June 2022, were included. CS was performed after confirming tumor to be M0 based on imaging and/or staging laparoscopy, except for resectable liver metastases. Preoperative chemotherapy was continued for at least 6 months provided that adverse events were manageable.

RESULTS

Of 125 eligible patients, 23 were treated with CS, achieving a conversion rate of 18.4% and an R0 resection rate of 91.3%. The median duration of preoperative chemotherapy was 8.5 months; the median number of cycles was eight. The highest conversion rate was observed in patients receiving first-line treatment (14.4%), followed by those receiving second and third lines (5.8% and 2.3%, respectively). The median survival time in patients who received CS was significantly longer than that in patients who continued chemotherapy alone (56.7 versus 16 months, respectively, P < 0.0001). There was no significant difference in the 3-year overall survival between the patients who achieved CS after first-line treatment (63.2%, n = 18) and those who achieved CS after second- or third-line treatment (66.7%, n = 5).

CONCLUSION

Consistent chemotherapy strategies could lead to successful CS and improved prognosis in a greater number of patients with cStage IVB GC, regardless of line of treatment.

Short-term clinical evaluation of teduglutide for patients with Crohn’s disease on home parenteral support for postoperative short bowel syndrome with intestinal failure

BACKGROUND & AIM

The short-term effects of teduglutide (TED) for short bowel syndrome with chronic intestinal failure (SBS-IF) in patients with Crohn's disease (CD) remain unknown. The aim of this study was to investigate the effects of TED in patients with CD on home parenteral support (PS) for SBS-IF.

METHODS

We retrospectively investigated the medical records of patients with CD associated with SBS-IF who initiated TED between 2020 and 2021. The primary outcomes were the change in PS volume and proportion of patients with a reduction of PS volume by ≥ 20% at week 8. Secondary outcomes were the change in PS volume in patients with CD without/with colon in continuity and adverse events during the observation period.

RESULTS

Eighteen patients with CD who underwent home PS for SBS-IF were included in this study. Two patients were excluded owing to intolerable abdominal pain or vomiting within 8 weeks (11%). Sixteen patients continued TED throughout the observation period. The median PS duration was 10.5 years. The median observation period was 22 weeks after starting TED. TED significantly reduced the PS volume from 15,825.0 mL/week to 10,700.0 mL/week (p = 0.0038), and the PS volume decreased by ≥ 20% in 7 patients (43.8%) at week 8. The PS volume was significantly reduced at week 4 (p = 0.0078) in 11 patients without colon in continuity but not in 5 patients with colon in continuity. Two patients successfully stopped home PS. No serious adverse events occurred.

CONCLUSIONS

TED administration significantly reduced PS volume at week 8 in patients with CD associated with SBS-IF, and at week 4 in patients without colon in continuity.

Crohn's Disease and Early Exposure to Thiopurines are Independent Risk Factors for Mosaic Chromosomal Alterations in Patients with Inflammatory Bowel Diseases

BACKGROUND AND AIMS

Mosaic chromosomal alterations [mCAs] increase the risk for haematopoietic malignancies and may be risk factors for several other diseases. Inflammatory bowel diseases [IBDs], including Crohn's disease [CD] and ulcerative colitis [UC], are associated with mCAs, and patients may be at risk for haematopoietic malignancy development and/or modification of IBD phenotypes. In the present study, we screened patients with IBD for the presence of mCAs and explored the possible pathophysiological and genetic risk factors for mCAs.

METHODS

We analysed mCAs in peripheral blood from 3339 patients with IBD and investigated the clinical and genetic risk factors for mCAs.

RESULTS

CD and exposure to thiopurines before the age of 20 years were identified as novel independent risk factors for mCAs [odds ratio = 2.15 and 5.68, p = 1.17e-2 and 1.60e-3, respectively]. In contrast, there were no significant associations of disease duration, anti-tumour necrosis factor alpha antibodies, or other clinical factors with mCAs. Gene ontology enrichment analysis revealed that genes specifically located in the mCAs in patients with CD were significantly associated with factors related to mucosal immune responses. A genome-wide association study revealed that ERBIN, CD96, and AC068672.2 were significantly associated with mCAs in patients with CD [p = 1.56e-8, 1.65e-8, and 4.92e-8, respectively].

CONCLUSIONS

The difference in mCAs between patients with CD and UC supports the higher incidence of haematopoietic malignancies in CD. Caution should be exercised when using thiopurines in young patients with IBD, particularly CD, in light of possible chromosomal alterations.

Genetic Background of Mesalamine-induced Fever and Diarrhea in Japanese Patients with Inflammatory Bowel Disease

BACKGROUND

Some patients with inflammatory bowel disease (IBD) who were under mesalamine treatment develop adverse reactions called "mesalamine allergy," which includes high fever and worsening diarrhea. Currently, there is no method to predict mesalamine allergy. Pharmacogenomic approaches may help identify these patients. Here we analyzed the genetic background of mesalamine intolerance in the first genome-wide association study of Japanese patients with IBD.

METHODS

Two independent pharmacogenetic IBD cohorts were analyzed: the MENDEL (n = 1523; as a discovery set) and the Tohoku (n = 788; as a replication set) cohorts. Genome-wide association studies were performed in each population, followed by a meta-analysis. In addition, we constructed a polygenic risk score model and combined genetic and clinical factors to model mesalamine intolerance.

RESULTS

In the combined cohort, mesalamine-induced fever and/or diarrhea was significantly more frequent in ulcerative colitis vs Crohn's disease. The genome-wide association studies and meta-analysis identified one significant association between rs144384547 (upstream of RGS17) and mesalamine-induced fever and diarrhea (P = 7.21e-09; odds ratio = 11.2). The estimated heritability of mesalamine allergy was 25.4%, suggesting a significant correlation with the genetic background. Furthermore, a polygenic risk score model was built to predict mesalamine allergy (P = 2.95e-2). The combined genetic/clinical prediction model yielded a higher area under the curve than did the polygenic risk score or clinical model alone (area under the curve, 0.89; sensitivity, 71.4%; specificity, 90.8%).

CONCLUSIONS

Mesalamine allergy was more common in ulcerative colitis than in Crohn's disease. We identified a novel genetic association with and developed a combined clinical/genetic model for this adverse event.

Clinical Characteristics and Risk Factors for Pneumocystis Jirovecii Pneumonia during Immunosuppressive Treatment in Patients with Ulcerative Colitis: A Retrospective Study

AIMS

This study aimed to clarify the clinical characteristics of Pneumocystis jirovecii pneumonia (PJP) infection in patients with ulcerative colitis (UC) and to identify risk factors for PJP using a retrospective case-control study.

METHODS

Of 4,525 patients with UC treated between 2007 and 2019, we identified those who satisfied the criteria for PJP. The Lichtiger clinical activity index (LCI) was compared between the initiation of immunosuppressive drug treatment and the onset of PJP. A retrospective case-control study was conducted using a PJP group and a non-PJP group.

RESULTS

Nine patients experienced PJP, of whom two died. Since October 2014, there were no cases of PJP among UC patients aged ≥50 years who were prescribed three or more immunosuppressive agents given prophylactic sulfamethoxazole-trimethoprim (TPM-SMX). The median LCI (range) was 13 (8-17) at the initiation of treatment versus 2 (1-8) at PJP onset (p = 0.016). The median time to PJP onset was 83 days after treatment initiation. In the PJP group the median age was significantly greater (p = 0.022), three immunosuppressants were used significantly more frequently (p = 0.004), and the lymphocyte counts during treatment were significantly lower (p < 0.01) than in the non-PJP group. The cut-off lymphocyte count that distinguished PJP patients from non-PJP patients was 570/μL according to a receiver-operating curve analysis.

CONCLUSIONS

Prophylactic administration of TPM-SMX prevented further cases of PJP. The onset of PJP occurred at the same time as the symptoms of UC were stabilizing and the immunosuppressive drugs were being reduced. Greater age, lower lymphocyte count, and treatment with three immunosuppressive drugs were risk factors for PJP.

An increase in LRRK2 suppresses autophagy and enhances Dectin-1-induced immunity in a mouse model of colitis

The LRRK2/MUC19 gene region constitutes a high-risk genetic locus for the occurrence of both inflammatory bowel diseases (IBDs) and Parkinson's disease. We show that dendritic cells (DCs) from patients with Crohn's disease (CD) and lymphoblastoid cell lines derived from patients without CD but bearing a high-risk allele (rs11564258) at this locus as heterozygotes exhibited increased LRRK2 expression in vitro. To investigate the immunological consequences of this increased LRRK2 expression, we conducted studies in transgenic mice overexpressing Lrrk2 and showed that these mice exhibited more severe colitis induced by dextran sodium sulfate (DSS) than did littermate control animals. This increase in colitis severity was associated with lamina propria DCs that showed increased Dectin-1-induced NF-κB activation and proinflammatory cytokine secretion. Colitis severity was driven by LRRK2 activation of NF-κB pathway components including the TAK1 complex and TRAF6. Next, we found that membrane-associated LRRK2 (in association with TAB2) caused inactivation of Beclin-1 and inhibition of autophagy. HCT116 colon epithelial cells lacking Beclin-1 exhibited increased LRRK2 expression compared to wild-type cells, suggesting that inhibition of autophagy potentially could augment LRRK2 proinflammatory signaling. We then showed that LRRK2 inhibitors decreased Dectin-1-induced TNF-α production by mouse DCs and ameliorated DSS-induced colitis, both in control and Lrrk2 transgenic animals. Finally, we demonstrated that LRRK2 inhibitors blocked TNF-α production by cultured DCs from patients with CD. Our findings suggest that normalization of LRRK2 activation could be a therapeutic approach for treating IBD, regardless of whether a LRRK2 risk allele is involved.

NUDT15 codon 139 is the best pharmacogenetic marker for predicting thiopurine-induced severe adverse events in Japanese patients with inflammatory bowel disease: a multicenter study

BACKGROUND

Despite NUDT15 variants showing significant association with thiopurine-induced adverse events (AEs) in Asians, it remains unclear which variants of NUDT15 or whether additional genetic variants should be tested to predict AEs. To clarify the best pharmacogenetic test to be used clinically, we performed association studies of NUDT15 variants and haplotypes with AEs, genome-wide association study (GWAS) to discover additional variants, and ROC analysis to select the model to predict severe AEs.

METHODS

Overall, 2630 patients with inflammatory bowel disease (IBD) were enrolled and genotyped for NUDT15 codon 139; 1291 patients were treated with thiopurines. diplotypes were analyzed in 970 patients, and GWASs of AEs were performed with 1221 patients using population-optimized genotyping array and imputation.

RESULTS

We confirmed the association of NUDT15 p.Arg139Cys with leukopenia and alopecia (p = 2.20E-63, 1.32E-69, OR = 6.59, 12.1, respectively), and found a novel association with digestive symptoms (p = 6.39E-04, OR = 1.89). Time to leukopenia was significantly shorter, and when leukopenia was diagnosed, thiopurine doses were significantly lower in Arg/Cys and Cys/Cys than in Arg/Arg. In GWASs, no additional variants were found to be associated with thiopurine-induced AEs. Despite strong correlation of leukopenia frequency with estimated enzyme activities based on the diplotypes (r² = 0.926, p = 0.0087), there were no significant differences in the AUCs of diplotypes from those of codon 139 to predict severe AEs (AUC = 0.916, 0.921, for acute severe leukopenia, AUC = 0.990, 0.991, for severe alopecia, respectively).

CONCLUSIONS

Genotyping of NUDT15 codon 139 was sufficient to predict acute severe leukopenia and alopecia in Japanese patients with IBD.

NUDT15, FTO, and RUNX1 genetic variants and thiopurine intolerance among Japanese patients with inflammatory bowel diseases

Background/Aims

Recent genome-wide analyses have provided strong evidence concerning adverse events caused by thiopurine drugs such as azathioprine (AZA) and 6-mercaptopurine. The strong associations identified between NUDT15 p.Arg139Cys and thiopurine-induced leukopenia and severe hair loss have been studied and confirmed over the last 2 years. However, other coding variants, including NUDT15 p.Val18_Val19insGlyVal, NUDT15 p.Val18Ile, and FTO p.Ala134Thr, and a noncoding variation in RUNX1 (rs2834826) remain to be examined in detail in this respect. Therefore, we investigated the correlation between these adverse events and the 5 recently identified variants mentioned above among Japanese patients with inflammatory bowel diseases (IBD).

Methods

One hundred sixty thiopurine-treated patients with IBD were enrolled. Genotyping was performed using TaqMan SNP Genotyping Assays or Sanger sequencing.

Results

None of the 5 variants were associated with gastrointestinal intolerance to AZA. However, NUDT15 p.Arg139Cys was significantly associated with the interval between initiation and discontinuation of AZA among patients with gastrointestinal intolerance. This variant was strongly associated with early (<8 weeks) and late (≥8 weeks) leukopenia and severe hair loss. Moreover, it correlated with the interval between initiation of thiopurine therapy and leukopenia occurrence, and average thiopurine dose. NUDT15 p.Val18_Val19insGlyVal, NUDT15 p.Val18Ile, FTO p.Ala134Thr, and RUNX1 rs2834826 exhibited no significant relationship with the adverse events examined.

Conclusions

Of the 5 variants investigated, NUDT15 p.Arg139Cys had the strongest impact on thiopurine-induced leukopenia and severe hair loss; therefore, its genotyping should be prioritized over that of other variants in efforts to predict these adverse events in Japanese patients with IBD.

Safety of One-Week, First-Line, Standard Triple Therapy for Helicobacter Pylori Eradication in a Japanese Population

BACKGROUND

Standard triple therapy with the proton pump inhibitors, clarithromycin and amoxicillin for Helicobacter pylori infection is considered to be safe; however, the development of significant adverse events (AEs), such as skin rashes, has been reported.

OBJECTIVE

To reconfirm the safety of this treatment.

METHODS

This was a retrospective cohort study. After the exclusion of patients allergic to penicillin, 322 consecutive patients, consisting of 305 outpatients and 17 inpatients, had received the first-line eradication treatment with lansoprazole (30 mg), clarithromycin (200 mg), and amoxicillin (750 mg) twice daily for 7 days. Their medical charts were reviewed, and data were collected.

RESULTS

Three patients discontinued the treatment because of the development of a skin rash, mild diarrhea, and heat sensation, respectively. The main AE observed was mild diarrhea in 50 patients. One patient had frequent diarrhea, but it was readily resolved by a probiotic treatment. On the second or third day after the conclusion of the treatment, a skin rash also occurred in six patients (2%). Two of these patients and one patient who discontinued the treatment were administered steroids as outpatients. They recovered within 1 month.

CONCLUSION

Most AEs that developed were mild, except for some cases of a rash. Rashes developed in spite of the exclusion of penicillin-allergic patients and mainly after the completion of the one-week treatment. As a consequence of little previous exposure to penicillin in the Japanese population, the development of delayed rashes after this exclusion may represent first sensitization to penicillin.

Antigen-Specific IgG ameliorates allergic airway inflammation via Fcγ receptor IIB on dendritic cells

Background

There have been few reports on the role of Fc receptors (FcRs) and immunoglobulin G (IgG) in asthma. The purpose of this study is to clarify the role of inhibitory FcRs and antigen presenting cells (APCs) in pathogenesis of asthma and to evaluate antigen-transporting and presenting capacity by APCs in the tracheobronchial mucosa.

Methods

In FcγRIIB deficient (KO) and C57BL/6 (WT) mice, the effects of intratracheal instillation of antigen-specific IgG were analysed using the model with sensitization and airborne challenge with ovalbumin (OVA). Thoracic lymph nodes instilled with fluorescein-conjugated OVA were analysed by fluorescence microscopy. Moreover, we analysed the CD11c⁺ MHC class II⁺ cells which intaken fluorescein-conjugated OVA in thoracic lymph nodes by flow cytometry. Also, lung-derived CD11c⁺ APCs were analysed by flow cytometry. Effects of anti-OVA IgG1 on bone marrow dendritic cells (BMDCs) in vitro were also analysed. Moreover, in FcγRIIB KO mice intravenously transplanted dendritic cells (DCs) differentiated from BMDCs of WT mice, the effects of intratracheal instillation of anti-OVA IgG were evaluated by bronchoalveolar lavage (BAL).

Results

In WT mice, total cells and eosinophils in BAL fluid reduced after instillation with anti-OVA IgG1. Anti-OVA IgG1 suppressed airway inflammation in hyperresponsiveness and histology. In addition, the number of the fluorescein-conjugated OVA in CD11c⁺ MHC class II⁺ cells of thoracic lymph nodes with anti-OVA IgG1 instillation decreased compared with PBS. Also, MHC class II expression on lung-derived CD11c⁺ APCs with anti-OVA IgG1 instillation reduced. Moreover, in vitro, we showed that BMDCs with anti-OVA IgG1 significantly decreased the T cell proliferation. Finally, we demonstrated that the lacking effects of anti-OVA IgG1 on airway inflammation on FcγRIIB KO mice were restored with WT-derived BMDCs transplanted intravenously.

Conclusion

Antigen-specific IgG ameliorates allergic airway inflammation via FcγRIIB on DCs.

Resolvin E1, an endogenous lipid mediator derived from eicosapentaenoic acid, prevents dextran sulfate sodium-induced colitis

BACKGROUND

Resolvin E1 (RvE1), an endogenous lipid mediator derived from eicosapentaenoic acid, has been identified in local inflammation during the healing stage. RvE1 reduces inflammation in several types of animal models including peritonitis and retinopathy and blocks human neutrophil transendothelial cell migration. The RvE1 receptor ChemR23 is expressed on myeloid cells such as macrophages and dendritic cells. The aim of this study was to determine whether RvE1 regulates colonic inflammation when the innate immune response of macrophages plays a key role in pathogenesis and tissue damage.

METHODS

The RvE1 receptor ChemR23 was expressed in mouse peritoneal macrophages as defined by flow cytometry. Peritoneal macrophages were pretreated with RvE1, followed by lipopolysaccharide stimulation, whereupon transcriptional levels of proinflammatory cytokines were analyzed.

RESULTS

RvE1 treatment led to inhibition of proinflammatory cytokines including TNF-alpha and IL-12p40. In HEK293 cells, pretreatment with RvE1 inhibited TNF-alpha-induced nuclear translocation of NF-kappaB in a ChemR23-dependent manner. These results suggested that RvE1 could regulate proinflammatory responses of macrophages expressing ChemR23. Therefore, we investigated the beneficial effects of RvE1 in dextran sulfate sodium-induced colitis. RvE1 treatment led to amelioration of colonic inflammation.

CONCLUSIONS

These results indicate that RvE1 suppresses proinflammatory responses of macrophages. RvE1 and its receptor may therefore be useful as therapeutic targets in the treatment of human inflammatory bowel disease and other inflammatory disorders.

IgG transport across mucosal barriers by neonatal Fc receptor for IgG and mucosal immunity

Mucosal secretions of the human gastrointestinal, respiratory, and genital tracts contain significant quantities of IgG. The neonatal Fc receptor for IgG (FcRn) plays a major role in regulating host IgG levels and transporting IgG and associated antigens across polarized epithelial barriers. The FcRn can then recycle the IgG/antigen complex back across the intestinal barrier into the lamina propria for processing by dendritic cells and presentation to CD4(+) T cells in regional organized lymphoid structures. FcRn, through its ability to secrete and absorb IgG, thus integrates luminal antigen encounters with systemic immune compartments and, as such, provides essential host defense and immunoregulatory functions at the mucosal surfaces.

Association between IL-18 gene promoter polymorphisms and inflammatory bowel disease in a Japanese population

BACKGROUND

Interleukin-18 (IL-18) is a pleiotropic cytokine that induces the production of interferon (IFN)-gamma and also to regulate Th2 cytokines. Recently, association studies between IL-18 gene promoter polymorphisms and several Th1- or Th2-mediated inflammatory diseases were reported. In inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), recent evidence suggests that IL-18 is involved in the pathogenesis.

METHODS

Using DNA direct sequencing, we investigated IL-18 gene promoter polymorphisms at -607C/A and -137G/C. Allele, genotype, and haplotype frequencies were determined in 210 Japanese patients with UC, 205 patients with CD, and 212 controls.

RESULTS

In UC, the -137C allele frequency was significantly higher in the proctitis-type patients than in controls (Pc = 0.0068). The -137 genotype frequency was also significantly different in the proctitis-type patients than in controls (Pc = 0.032). No other allele and genotype frequencies were significantly associated with UC after Bonferroni correction. Furthermore, the frequency of haplotype 2 (-607A, -137C), which had a lower promoter activity and IFN-gamma mRNA level than the other haplotypes as previously reported, was significantly higher in the proctitis-type patients than in controls (Pc = 0.01). In CD, we could not find any significant differences.

CONCLUSIONS

IL-18 gene promoter polymorphisms may not be associated with disease susceptibility but related to the extent of disease in UC.

Mechanism of carcinogenesis in familial tumors

It is thought that malignant tumors occur through interactions of multiple environmental factors and a personal genetic factor. A normal somatic cell having an intrinsic function is able to acquire the characteristics of a malignant cell under the influence of many factors. A small percentage of all tumors have obvious familial aggregation. These entities are called familial cancer. The familial cancer syndrome is well defined for colorectal cancer, breast cancer, endocrine neoplasia, and so on. Traits of familial tumors are sequentially inherited by offspring through gametes in a Mendelian fashion, most commonly in an autosomal-dominant manner. Carcinogenesis requires multiple genetic events. A patient with a familial tumor is ahead of an individual without any germline mutation in the carcinogenesis process. In such a situation, patients frequently suffer from multiple malignant tumors at a young age. It is well known that three major genes are closely related to the cell cycle and tumorigenesis. These gene types are protooncogenes, tumor suppressor genes, and DNA mismatch repair genes. Proto-oncogenes function to accelerate cells during the G1 or growth phase of the cell cycle. Tumor suppressor genes act as blocks against cell growth and proliferation. Inactivation of tumor suppressor genes requires alterations in both alleles. These phenomena are known as Knudson's two-hits theory. However, DNA mismatch repair genes are known as caretaker genes and correct mismatch pair generation during DNA replication. Germline mutation of DNA mismatch repair genes causes hereditary nonpolyposis colorectal cancer. The tumor phenotype from patients with hereditary nonpolyposis colorectal cancer is demonstrated to be microsatellite instability positive.

[Study on fatigue toughness of dental materials. 1. Compressive strength on various luting cements and composite resin cores]

In this study, we investigated compressive strength of various luting cements and composite resin cores in both dry and wet condition, and then influences of repeating load on compressive strength in wet condition of distilled water at 37 degrees C. As frequency of repeating load increased, compressive strength of all materials decreased. It means that the repeated load cycling test used in this study is adequate for evaluating durability of various dental materials. The results were as follows: 1. In the condition of no loading in both dry and wet condition, resin cement indicated the highest compressive strength of all cements examined and was followed by glass ionomer cement, zinc phosphate cement and polycarboxylate cement. Glass ionomer cement was notably influenced in wet condition. 2. After 10,000 cycles of loading in wet condition, resin cement indicated the highest compressive strength again and was followed by glass ionomer cement, polycarboxylate cement and zinc phosphate cement. In particular, compressive strength of zinc phosphate cement decreased remarkably. 3. In the condition of no loading, visible light-cured composite resin core was superior to chemical one. Visible light one was notably influenced in wet condition. 4. After 10,000 cycles of loading, visible light-cured composite resin core was superior to chemical one.