Fumihiko Tanioka

Genetic variation in PSCA is associated with susceptibility to diffuse-type gastric cancer

Gastric cancer is classified into intestinal and diffuse types, the latter including a highly malignant form, linitis plastica. A two-stage genome-wide association study (stage 1: 85,576 SNPs on 188 cases and 752 references; stage 2: 2,753 SNPs on 749 cases and 750 controls) in Japan identified a significant association between an intronic SNP (rs2976392) in PSCA (prostate stem cell antigen) and diffuse-type gastric cancer (allele-specific odds ratio (OR) = 1.62, 95% CI = 1.38–1.89, P = 1.11 × 10−9). The association was far less significant in intestinal-type gastric cancer. We found that PSCA is expressed in differentiating gastric epithelial cells, has a cell-proliferation inhibition activity in vitro and is frequently silenced in gastric cancer. Substitution of the C allele with the risk allele T at a SNP in the first exon (rs2294008, which has r2 = 0.995, D′ = 0.999 with rs2976392) reduces transcriptional activity of an upstream fragment of the gene. The same risk allele was also significantly associated with diffuse-type gastric cancer in 457 cases and 390 controls in Korea (allele-specific OR = 1.90, 95% CI = 1.56–2.33, P = 8.01 × 10−11). The polymorphism of the PSCA gene, which is possibly involved in regulating gastric epithelial-cell proliferation, influences susceptibility to diffuse-type gastric cancer.

A Functional Single Nucleotide Polymorphism in Mucin 1, at Chromosome 1q22, Determines Susceptibility to Diffuse-Type Gastric Cancer

BACKGROUND & AIMS Two major types of gastric cancer, intestinal and diffuse, develop through distinct mechanisms; the diffuse type is considered to be more influenced by genetic factors, although the mechanism is unknown. Our previous genome-wide association study associated 3 single nucleotide polymorphisms (SNPs) with diffuse-type gastric cancer (DGC); 1 was a functional SNP (rs2294008) in prostate stem cell antigen (PSCA), but the loci of the other 2 were not investigated. METHODS We performed high-density mapping to explore a linkage disequilibrium status of the 2 SNPs at chromosome 1q22. A DGC case-control study was conducted using DNA from 606 cases and 1264 controls (all Japanese individuals) and validated using DNA from Japanese (304 cases, 1465 controls) and Korean (452 cases, 372 controls) individuals. The effects of SNPs on function were analyzed by reporter assays and analyses of splice variants. RESULTS A region of a strong linkage disequilibrium with the 2 SNPs contained mucin 1 (MUC1) and other 4 genes and SNPs significantly associated with DGC (rs2070803: P = 4.33 × 10(-13); odds ratio [OR], 1.71 by meta-analysis of the studies on the 3 panels) but not with intestinal-type gastric cancer. Functional studies demonstrated that rs4072037 (P = 1.43 × 10(-11); OR, 1.66 by meta-analysis) in MUC1 affects promoter activity and determines the major splicing variants of MUC1 in the gastric epithelium. Individuals that carry both SNPs rs2294008 in PSCA and rs4072037 in MUC1 have a high risk for developing DGC (OR, 8.38). CONCLUSIONS MUC1 is the second major DGC susceptibility gene identified. The SNPs rs2070803 and rs4072037 in MUC1 might be used to identify individuals at risk for this type of gastric cancer.

Overexpression of MUC13 is associated with intestinal-type gastric cancer

Mucins are secreted or transmembrane glycoproteins that are expressed mainly in the digestive tract. This family of proteins has been the focus of much gastric cancer research as some transmembrane mucins are implicated in tumorigenesis and make attractive targets for cancer diagnosis and therapeutics. Mucins have also been utilized to classify gastric cancer by differentiating between gastric and intestinal phenotypes. Here we show that transmembrane mucin MUC13 is upregulated in gastric cancer. By quantitative real‐time reverse transcription‐polymerase chain reaction and immunoblot analysis, overexpression of MUC13 was verified in more than half of the samples examined. In immunohistochemical analysis, MUC13 staining was observed in 74 of 114 cases of gastric cancer (64.9%), predominantly in intestinal type (P < 0.001), and in 9 of 10 cases of intestinal metaplasia, precancerous lesions of intestinal‐type gastric cancer, but not observed in normal gastric mucosa. Moreover, MUC13 staining patterns characteristic of histological type were identified: staining was on the apical side of tubular glands in intestinal type and on the cytoplasm in diffuse type. These results suggest that MUC13 is a good differentiation marker for gastrointestinal mucosa and that it may have a causal role that correlates with two distinct gastric tumorigenesis pathways. (Cancer Sci 2005; 96: 265 –274)

Solid–papillary carcinoma of the breast: Clinicopathological study of 20 cases

The purpose of the present paper was to evaluate the clinicopathological and biological features of 20 Japanese patients with solid–papillary carcinoma of the breast (SPC) or SPC associated with invasive breast cancer. All the patients were Japanese women, including two sisters. The mean age was 66.0 years. The incidence of SPC among all the breast cancers treated at two institutions was 1.1% and 1.7%, respectively. The mean disease‐free interval was 4 years 11 months. Axillary lymph node metastasis or tumor recurrence did not occur in any of the cases. Fifteen cases of SPC contained invasive cancers that ranged from <5% to 60% of the entire tumor area. Histological types of invasive cancers were mucinous carcinoma in five cases and neuroendocrine cell carcinoma in 10 cases. These results indicate that SPC is a potential precursor lesion for neuroendocrine carcinoma as well as mucinous carcinoma. When all the cases were classified and analyzed according to both the 2002 tumor node metastasis (TNM) classification system and the Nottingham histological grade, SPC patients, even those with invasive cancers, seemed to have longer disease‐free survival compared to patients with the other invasive breast cancers of matching grade and stage. Clinicopathologically, SPC could be regarded as a separate type of ductal carcinoma in situ.

Germline alterations in the CDH1 gene in familial gastric cancer in the Japanese population

Germline point or small frameshift mutations of the CDH1 (E‐cadherin) gene are known to cause familial gastric cancer (FGC), but the frequency of CDH1 mutations is low in Japanese patients with FGC. Because recent studies have reported germline large genomic deletions of CDH1 in European and Canadian patients with FGC, in the present study we examined DNA samples from 13 Japanese patients with FGC to determine whether similar germline changes were present in CDH1 in this population. Using a sequencing analysis, a 1‐bp deletion (c.1212delC), leading to the production of a truncated protein (p.Asn405IlefsX12), was found in an FGC family; immunohistochemical analysis revealed the loss of CDH1 protein expression in the tumors in this family. Using a combination of multiplex ligation‐dependent probe amplification (MLPA) and RT‐PCR analyses, we also found a large genomic deletion (c.164‐?_387+?del), leading to the loss of exon 3 and the production of a truncated protein (p.Val55GlyfsX38), in another FGC family. The functional effects of the detected mutations were examined using a slow aggregation assay. Significant impairment of cell–cell adhesion was detected in CHO‐K1 cells expressing Ile405fsX12‐ and Gly55fsX38‐type CDH1 compared with cells expressing wild‐type CDH1. Our results suggest that the p.Asn405IlefsX12 and p.Val55GlyfsX38 mutations of the CDH1 gene contribute to carcinogenesis in patients with FGC. This is the first report of CDH1 germline truncating mutations in Japanese patients with FGC. Screening for large germline rearrangements should be included in CDH1 genetic testing for FGC. (Cancer Sci 2011; 102: 1782–1788)

Fluorescence in situ hybridization analysis with a tissue microarray: 'FISH and chips' analysis of pathology archives

Practicing pathologists expect major somatic genetic changes in cancers, because the morphological deviations in the cancers they diagnose are so great that the somatic genetic changes to direct these phenotypes of tumors are supposed to be correspondingly tremendous. Several lines of evidence, especially lines generated by high‐throughput genomic sequencing and genome‐wide analyses of cancer DNAs are verifying their preoccupations. This article reviews a comprehensive morphological approach to pathology archives that consists of fluorescence in situ hybridization with bacterial artificial chromosome (BAC) probes and screening with tissue microarrays to detect structural changes in chromosomes (copy number alterations and rearrangements) in specimens of human solid tumors. The potential of this approach in the attempt to provide individually tailored medical practice, especially in terms of cancer therapy, is discussed.

Interaction of EphB2-tyrosine kinase receptor and its ligand conveys dorsalization signal in Xenopus laevis development.

The Eph class is the largest family of receptor tyrosine kinases and has been shown to play various roles in neural development including axon pathfinding and neural crest migration. EphB2 associates with transmembrane ligands Ephrin-B1 and -B2, which leads to tyrosine phosphorylation of both the ligands and receptor and is presumed to regulate cell-to-cell interactions by bidirectional signaling. We have investigated the biological effects of the EphB2-induced signal in the early stage of Xenopus laevis development. Xenopus EphB2 transcripts were detected maternally and were expressed at equal levels between the ventral and dorsal halves of the gastrulae, with expression increasing after the late gastrula stage. EphB2 mRNA expression in dorsal marginal zone explants from gastrulae increases during later development while that in ventral explants does not. We show here that microinjection of RNA encoding EphB2 into a ventral blastomere of embryos induced a partial secondary dorsal axis which consisted of neural tissues, notochord and somites. Analysis with molecular markers verified that the microinjected EphB2 dorsalized the mesoderm of ventral marginal zone explants. These dorsalizing effects of EphB2 in both the whole embryo and ventral explants were inhibited by the coinjection of RNA encoding the soluble form of Ephrin-B1. Furthermore, co-injection of EphB2 and Ephrin-B1 RNAs synergistically enhanced the dorsalization effect. These data show that the interaction between EphB2 and its ligands including Ephrin-B1 causes signaling events which lead to dorsal development, and strongly suggests the existence of proteins which mediate the dorsalization induced by EphB2 in early stage embryos of Xenopus laevis.

CD5^+ Diffuse Large B-Cell Lymphoma with c-myc/IgH Rearrangement Presenting as Primary Effusion Lymphoma

We report an instructive case of diffuse large B-cell lymphoma presenting as acute heart failure. A 69-year-old human immunodeficiency virus-negative man was admitted to our hospital for general fatigue. A computed tomographic scan of the chest and abdomen showed pericardial effusion, but there was no evidence of tumor masses, lymph node enlargement, or hepatosplenomegaly. During the chemotherapy, increased lactate dehydrogenase and pleural effusion appeared. The tumor cells in the effusion showed positivity for CD5, CD19, CD20, κ chain, and Bcl-2 and negativity for CD10 and CD23.The chromosomes showed t(8;14)(q24;q32) with c-myc/immunoglobulin (Ig)H rearrangement, and the MIB-1 index was not high (60%). Neither human herpes virus 8 nor Epstein-Barr virus DNA was detected in the cells by polymerase chain reaction. The response to chemotherapy was very poor, and the patient died 4 months after the diagnosis. A spectrum of the symptoms of CD5+ lymphoma encompasses pericardial effusion and also can accompany c-myc/IgH rearrangement.

Association between dopamine beta hydroxylase rs5320 polymorphism and smoking behaviour in elderly Japanese

The dopaminergic brain pathway is involved in many addictive behaviours, hence represents a good candidate in the study of smoking behaviour and nicotine addiction. Dopamine beta hydroxylase (DBH) is an enzyme that catalyses the conversion of dopamine into noradrenaline. This study, the first of its kind, was done to investigate the role of DBH rs5320 polymorphism in smoking behaviour of elderly Japanese. This was done by collecting blood samples from 2521 subjects with various smoking habits to genotype the DBH rs5320 polymorphism. Participants also had to fill out a questionnaire containing questions regarding their lifestyles. Some of the questions were from the Fagerström Test for Nicotine Dependence (FTND) and the Tobacco Dependence Screener (TDS). It was found that male ever-smokers with AA genotype smoked less cigarettes per day than those with GG and AG genotypes. FTND scores were also lowest in male ever-smokers with AA genotype and in female ever-smokers with AG genotype. There was no correlation detected between the TDS scores and any of the genotypes. This study shows that DBH rs5320 polymorphism influences nicotine dependence.

Robust quantitative assessments of cytosine modifications and changes in the expressions of related enzymes in gastric cancer

BackgroundThe rediscovery of 5-hydroxymethylcytosine, the ten-eleven translocation (TET) family, thymine-DNA glycosylase (TDG) and isocitrate dehydrogenase (IDH) have opened new avenues in the study of DNA demethylation pathways in gastric cancer (GC). We performed a comprehensive and robust analysis of these genes and modified cytosines in gastric cancer.MethodsLiquid chromatography mass spectrometry/mass spectrometry (LC-MS/MS) was used to assess 5-methyldeoxycytidine (5-mC), 5-hydroxymethyldeoxycytidine (5-hmC), 5-formyldeoxycytidine (5-fC) and 5-carboxyldeoxycytidine (5-caC) quantitatively in tumorous and non-tumorous regions of GCs; [D2]-5-hmC was used as an internal standard. Expression levels of the genes TET1, TET2, TET3, TDG, IDH1 and IDH2 were measured using a real-time reverse transcription polymerase chain reaction (RT-PCR) and were compared to the clinical attributes of each case. Using HEK293T cells the effects of introducing plasmids containing full-length TET1,TET2, and TET3 and 7 variants of the TET2 catalytic domain were evaluated in terms of their effect on cytosine demethylation.ResultsLC-MS/MS showed that 5-hmC was significantly decreased in tumorous portions. 5-mC was also moderately decreased in tumors, while 5-fC and 5-caC were barely detectable. The expressions of TET1, TET2, TET3, TDG and IDH2, but not IDH1, were notably decreased in GCs, compared with the adjacent non-tumor portion. TET1 expression and the 5-hmC levels determined using LC-MS/MS had a significantly positive correlation and TET1 protein had a greater effect on the increase in 5-hmC than TET2 and TET3 in HEK293T cells.ConclusionsThe loss of 5-hmC and the down-regulation of TET1-3, TDG and IDH2 were found in GCs. The loss of 5-hmC in GCs was mainly correlated with the down-regulation of TET1.