鯉沼 広治

A subset of colorectal carcinomas (CRCs) is associated with microsatellite instability (MSI) of the genome. Although extensive methylation of CpG islands within the promoter regions of DNA mismatch repair genes such as MLH1 is thought to play a central role in tumorigenesis for MSI-positive sporadic CRCs, it has been obscure whether such aberrant epigenetic regulation occurs more widely and affects other cancer-related genes in vivo. Here, by using methylated CpG island amplification coupled with representational difference analysis (MCA-RDA), we screened genomic fragments that are selectively methylated in CRCs positive for MLH1 methylation, resulting in the identification of hundreds of CpG islands containing genomic fragments. Methylation status of such CpG islands was verified for 28 genomic clones in 8 CRC specimens positive for MLH1 methylation and the corresponding paired normal colon tissue as well as in 8 CRC specimens negative for methylation. Many of the CpG islands were preferentially methylated in the MLH1 methylation-positive CRC specimens, although methylation of some of them was more widespread. These data provide insights into the complex regulation of the methylation status of CpG islands in CRCs positive for MSI and MLH1 methylation.

Pancreatic ductal carcinoma (PDC) remains one of the most intractable malignancies in humans. In order to clarify the molecular events underlying the carcinogenesis in PDC, we constructed a retroviral cDNA expression library from a PDC cell line, and used it to screen transforming genes in PDC by a focus formation assay with mouse 3T3 fibroblasts. We could obtain a total of 30 transformed cell foci in the screening, and one of the cDNA inserts harvested from such cell clones turned out to encode a wild-type human ARAF1. Unexpectedly, a long terminal repeat-driven overexpression of ARAF1 mRNA was confirmed to induce transformed foci in fibroblasts. The oncogenic potential of ARAF1 was examined by injecting the transformed fibroblasts into athymic nude mice. Importantly, ARAF1 mRNA was highly expressed in pancreatic ductal cell specimens purified from patients with PDC. These results have unveiled the transforming potential of ARAF1 protein, and also suggest that quantity of intracellular ARAF1 may be important in carcinogenesis of various human cancers.

The acetylation status of core histones in cardiomyocytes has been linked to the development of cardiac hypertrophy and heart failure. Little is known, however, of the genes affected by abnormal histone acetylation in such pathological conditions. We recently developed a genome-wide screening method, differential chromatin scanning (DCS), to isolate genomic fragments associated with histones subject to differential acetylation. We have now applied DCS to H9C2 rat embryonic cardiomyocytes incubated with or without trichostatin A (TSA), a specific inhibitor of histone deacetylase (HDAC) activity. About 200 genomic fragments were readily isolated by DCS on the basis of the preferential acetylation of associated histones in TSA-treated cells. Quantitation of the amount of DNA in chromatin immunoprecipitates prepared with antibodies to acetylated histone H3 revealed that 37 of 38 randomly chosen DCS clones were preferentially precipitated from the TSA-treated cells, thus verifying the high fidelity of DCS. Epigenetic regulation of DCS clones was further confirmed in cells treated with sodium butyrate, another HDAC inhibitor, as well as in cardiac myocytes isolated from neonatal rats. The mRNA level of 9 (39%) of 23 genes corresponding to DCS clones changed in parallel with the level of histone acetylation in H9C2 cells. Furthermore, a physiological hypertrophic stimulus, cardiotrophin-1, affected the acetylation level of histones associated with genomic regions corresponding to certain DCS clones. Our data thus establish a genome-wide profile of HDAC targets in cardiomyocytes, which should provide a basis for further investigations into the role of epigenetic modification in cardiac disorders.

Aggressive natural killer cell leukemia (ANKL) is an intractable malignancy that is characterized by the outgrowth of NK cells. To identify transforming genes in ANKL, we constructed a retroviral cDNA expression library from an ANKL cell line KHYG-1. Infection of 3T3 cells with recombinant retroviruses yielded 33 transformed foci. Nucleotide sequencing of the DNA inserts recovered from these foci revealed that 31 of them encoded KRAS2 with a glycine-to-alanine mutation at codon 12. Mutation-specific PCR analysis indicated that the KRAS mutation was present only in KHYG-1 cells, not in another ANKL cell line or in clinical specimens (n=8).

Pancreatic ductal carcinoma (PDC) remains one of the most intractable human malignancies, mainly because of the lack of sensitive detection methods. Although gene expression profiling by DNA microarray analysis is a promising tool for the development of such detection systems, a simple comparison of pancreatic tissues may yield misleading data that reflect only differences in cellular composition. To directly compare PDC cells with normal pancreatic ductal cells, we purified MUC1-positive epithelial cells from the pancreatic juices of 25 individuals with a normal pancreas and 24 patients with PDC. The gene expression profiles of these 49 specimens were determined with DNA microarrays containing >44 000 probe sets. Application of both Welch's analysis of variance and effect size-based selection to the expression data resulted in the identification of 21 probe sets corresponding to 20 genes whose expression was highly associated with clinical diagnosis. Furthermore, correspondence analysis and 3-D projection with these probe sets resulted in separation of the transcriptomes of pancreatic ductal cells into distinct but overlapping spaces corresponding to the two clinical classes. To establish an accurate transcriptome-based diagnosis system for PDC, we applied supervised class prediction algorithms to our large data set. With the expression profiles of only five predictor genes, the weighted vote method diagnosed the class of samples with an accuracy of 81.6%. Microarray analysis with purified pancreatic ductal cells has thus provided a basis for the development of a sensitive method for the detection of PDC.

A 57-year-old Japanese man had type II c gastric cancer with marked lymph node metastases associated with leukocytosis and elevated granulocyte colony-stimulating factor (G-CSF). Total gastrectomy and distal pancreatectomy with lymph node dissection were performed. Although the primary lesion was negative for G-CSF by histopathological immunostaining, a highly increased G-CSF m-RNA level, measured using reverse transcriptase-polymerase chain reaction in frozen sections, led to a diagnosis of G-CSF-producing gastric cancer. The leukocytes and G-CSF decreased immediately after surgery. He then had an intraabdominal recurrence, and was diagnosed with multiple tumors in his lung and brain, with abnormally elevated leukocytes and greatly increased G-CSF; he died 4 months after the surgery. Autopsy showed intraabdominal recurrence of cancer, with no metastases to the lung or brain, but with multiple brain and lung abscesses. We speculate that the excessively increased neutrophils induced by G-CSF infiltrated the lung and brain and formed abscesses, mimicking metastases.

Although acetylation-deacetylation of histones contributes to regulation of gene expression, few methods have been available to determine the whole-genome histone acetylation profile in specific cells or tissues. We have now developed a genome-wide screening method, differential chromatin scanning (DCS), to isolate genome fragments embedded in histones subject to differential acetylation. This DCS screening was applied to a human gastric cancer cell line incubated with or without an inhibitor of histone deacetylase (HDAC) activity, resulting in the rapid identification of more than 250 genome fragments. Interestingly, a number of cancer-related genes were revealed to be the targets of HDAC in the cancer cells, including those for tumour protein 73 and cell division cycle 34. Such differential acetylation of histone was also shown to be linked to the regulation of transcriptional activity of the corresponding genes. Among the isolated genome fragments, 94% (32/34) of them were confirmed to be bound to differentially acetylated histones, and the genes corresponding to 78% (7/9) of them exhibited differential transcriptional activity consistent with the level of histone acetylation. With its high fidelity, the DCS method should open a possibility to rapidly compare the genome-wide histone acetylation profiles and to provide novel insights into molecular carcinogenesis.

Alterations of the APC, K-ras, and beta-catenin genes are defined as early events in colorectal tumorigenesis. These alterations are well-known as constitutents of Vogelstein's pathway, however, the relationship among them is unclear. For understanding colorectal tumorigenesis it is important to evaluate their relationship. We analyzed the relationship between beta-catenin and K-ras gene mutations in clinical colorectal samples. Sixty-four cases of colorectal cancers (44 proximal, 20 distal) without a family history of colorectal cancer were used for this study. We purified genomic DNAs from fresh surgical samples and, thus, analyzed the mutations of beta-catenin (exon 3) and K-ras (codons 12 and 13) by PCR direct sequencing method using Big Dye terminator cycle sequencing with AmpliTaq polymerase FS. We found 27% (17/64) K-ras mutations (proximal 25%, 11/44; distal 30%, 6/20). The frequency of beta-catenin mutations was 11% (7/64; proximal 9%, 4/44; distal 15%, 3/20). All cases with beta-catenin mutation had no mutation of K-ras. All sites of beta-catenin mutation have been reported previously (codons 33, 34, 41, 45). In cell lines, it has been reported previously that beta-catenin and K-ras play the same roles in activation of cyclin D1 transcription. Our results may support this report and suggest that some colorectal cancers with beta-catenin mutation will progress without K-ras mutation. Further study may disclose a new pathway or new mechanism of colorectal tumorigenesis.

OBJECTIVE: Acute myeloid leukemia (AML) develops de novo or secondarily to either myelodysplastic syndrome (MDS) or anticancer treatment (therapy-related leukemia, TRL). Prominent dysplasia of blood cells is apparent in individuals with MDS-related AML as well as in some patients with TRL or even with de novo AML. The clinical entity of AML with multilineage dysplasia (AML-MLD) is likely to be an amalgamation of MDS-related AML and de novo AML-MLD. The aim of this study was to clarify, by the use of high-density oligonucleotide microarrays, whether these subcategories of AML are intrinsically distinct from each other. MATERIALS AND METHODS: The AC133+ hematopoietic stem cell-like fractions were purified from the bone marrow of individuals with de novo AML without dysplasia (n = 15), AML-MLD (n = 11), MDS-related AML (n = 11), or TRL (n = 2), and were subjected to the synthesis of cRNA which was subsequently hybridized to microarray harboring oligonucleotide corresponding to more than 12,000 probe sets. RESULTS: We could identify many genes whose expression was specific to these various subcategories of AML. Furthermore, with the correspondence analysis/three-dimensional projection strategy, we were able to visualize the independent, yet partially overlapping, nature of current AML subcategories on the basis of their transcriptomes. CONCLUSION: Our data indicate the possibility of subclassification of AML based on gene expression profiles of leukemic blasts.

To obtain insights into the molecular pathogenesis of heart failure in humans, we have analyzed the expression profiles of>12,000 genes in a total of 17 human specimens of right atrial myocytes. From this large data set, we here tried to identify gene clusters, expression level of which is correlated precisely with clinical parameter values of cardiac function. We could reveal that cardiac myocytes with normal sinus rhythm were clearly differentiated, in the point of view of gene expression, from those with atrial fibrillation. Further, an expression profile-based prediction of arrhythmia by a newly developed "weighted-distance method" could efficiently diagnose our samples. We could even construct calculation formulae for the values of left ventricular ejection fraction based on the expression level of selected genes. To our best knowledge, this is the first report to indicate that pumping ability of heart can be predicted by any measures of atrium.

Activating mutations of BRAF have been frequently observed in microsatellite unstable (MSI+) colorectal carcinomas (CRCs), in which mutations of BRAF and KRAS are mutually exclusive. Previously, we reported that hypermethylation of hMLH1 might play an important role in the tumorigenesis of right-sided sporadic CRCs with MSI showing less frequency of KRAS/TP53 alteration. Therefore, we have assumed that BRAF mutations might be highly associated with hMLH1 methylation status rather than MSI status. In this study, mutations of BRAF and KRAS and their relationship with MSI and hMLH1 methylation status were examined in 140 resected specimens of CRC. The methylation status was classified into 3 types: full methylation (FM), partial methylation (PM) and nonmethylation (NM). Only FM closely linked to reduced expression of hMLH1 protein. BRAF mutations were found in 16 cases (11%), all leading to the production of BRAF(V599E). As for MSI status, BRAF mutations were found in 43% of MSI+ and 4% of MSI- cases (p < 0.0001). Among the MSI+ individuals, BRAF mutations were more frequent in cases with hMLH1 deficiency (58%) than those with hMSH2 deficiency (0%; p=0.02). Moreover, they were found in 69% of FM, 4% of PM and 4% of NM, revealing a striking difference between FM and the other 2 groups (FM vs. PM or NM; p < 0.0001). These findings suggest that BRAF activation may participate in the carcinogenesis of sporadic CRCs with hMLH1 hypermethylation in the proximal colon, independently of KRAS activation.

直腸癌とS状結腸癌における下腸間膜動脈根リンパ節(253リンパ節)郭清の意義について検討した. 1980-1998年のD3郭清697例中253リンパ節転移陽性(253(+))症例は9例(1.29%)であり,この9例中8例に再発を認めた.再発は8例中6例で術後1年6カ月以内に認めた. 1990-1998年のD3郭清463例中253リンパ節転移陰性かつ中間リンパ節転移陽性(中間リンパ節(+))症例は24例(5.18%)であった.この24例中14例に再発を認めた(58.3%).再発は14例中12例で術後3年以内に認めた. 5年無再発生存率は253(+)症例が33.3%,中間リンパ節(+)症例が45.8%, 10年無再発生存率は253(+)症例が0.0%,中間リンパ節(+)症例が41.3%であった(p=0.045).以上より, 253(+)症例は少数かつ予後不良であり, 253(+)症例に対する253リンパ節郭清は予後を向上させないと考えられた.一方,中間リンパ節(+)症例では約半数は根治が得られ,中間リンパ節を郭清する意義は大きいと考えられた.

PURPOSE: Selective endoscopic resection may cure early colorectal cancer (T1), but the management is controversial. There is concern about the small risk of lymph node metastasis, which will not be treated by endoscopic resection alone. The authors sought predictive markers of lymph node metastasis to assist patient management. METHODS: The authors retrospectively analyzed consecutive cases of T1 stage colorectal cancer resected using endoscopic resection or bowel surgery over the period 1979 to 2000. The risk of lymph node metastasis was analyzed using logistic regression model for the markers selected by univariate analysis: the type of initial treatment, depth of submucosal invasion, lymphatic channel invasion, differentiation of histology, and invasive front histology. RESULTS: Two hundred seventy-eight patients were available for study. Twenty-one had lymph node metastasis. Depth of submucosal invasion (> or = 2,000 microm) and lymphatic channel invasion significantly predicted risk of lymph node metastasis in multivariate analysis. When these two factors were adopted for the prediction of lymph node metastasis, sensitivity, specificity, positive predictive value, and negative predictive value were 100, 55.6, 15.6, and 100 percent, respectively. CONCLUSIONS: Depth of submucosal invasion and lymphatic channel invasion were accurate predictive factors for lymph node metastasis. These two factors could be used in selecting appropriate cases for surgery after endoscopic resection.

Myelodysplastic syndrome (MDS) is a clonal disorder of haematopoietic stem cells. Despite the high incidence of MDS in the elderly, effective treatment of individuals in its advanced stages is problematic. DNA microarray analysis is a potentially informative approach to the development of new treatments for MDS. However, a simple comparison of 'transcriptomes' of bone marrow mononuclear cells among individuals at distinct stages of MDS would result in the identification of genes whose expression differences only reflect differences in the proportion of MDS blasts within bone marrow. Such a 'population shift' effect has now been avoided by purification of haematopoietic stem-like cells that are positive for the cell surface marker AC133 from the bone marrow of healthy volunteers and 30 patients at various stages of MDS. Microarray analysis with the AC133+ cells from these individuals resulted in the identification of sets of genes with expression that was specific to either indolent or advanced stages of MDS. The former group of genes included that for PIASy, which catalyses protein modification with the ubiquitin-like molecule SUMO. Induction of PIASy expression in a mouse myeloid cell line induced apoptosis. A loss of PIASy expression may therefore contribute directly to the growth of MDS blasts and stage progression.

DNA microarray analysis has been applied to identify molecular markers of human hematological malignancies. However, the relatively low correlation between the abundance of a given mRNA and that of the encoded protein makes it important to characterize the protein profile directly, or 'proteome,' of malignant cells in addition to the 'transcriptome.' To identify proteins specifically expressed in leukemias, here we isolated AC133(+) hematopoietic stem cell-like fractions from the bone marrow of 13 individuals with various leukemic disorders, and compared their protein profiles by two-dimensional electrophoresis. A total of 11 differentially expressed protein spots corresponding to 10 independent proteins were detected, and peptide fingerprinting combined with mass spectrometry of these proteins revealed them to include NuMA (nuclear protein that associates with the mitotic apparatus), heat shock proteins, and redox regulators. The abundance of NuMA in the leukemic blasts was significantly related to the presence of complex karyotype anomalies. Conditional expression of NuMA in a mouse myeloid cell line resulted in the induction of aneuploidy, cell cycle arrest in G(2)-M phases, and apoptosis. These results demonstrate the potential of proteome analysis with background-matched cell fractions obtained from fresh clinical specimens to provide insight into the mechanism of human leukemogenesis.

Dahl salt-sensitive rats are genetically hypersensitive to sodium intake. When fed a high sodium diet, they develop systemic hypertension, followed by cardiac hypertrophy and finally heart failure within a few months. Therefore, Dahl rats represent a good model with which to study how heart failure is developed in vivo. By using DNA microarray, we here monitored the transcriptome of >8000 genes in the left ventricular muscles of Dahl rats during the course of cardiovascular damage. Expression of the atrial natriuretic peptide gene was, for instance, induced in myocytes by sodium overload and further enhanced even at the heart failure stage. Interestingly, expression of the gene for the D-binding protein, an apoptotic-related transcriptional factor, became decreased upon the transition to heart failure. To our best knowledge, this is the first report to describe the transcriptome of cardiac myocytes during the disease progression of heart failure.

introduction: It is not clear whether flat lesions play a role in the pathogenesis of colorectal carcinoma. Flat lesions are being increasingly recognised with new colonoscopic techniques. Materials and Methods: A total of 10,939 consecutive colonoscopies were performed over a 9-year period. After bowel preparation with polyethylene glycol electrolyte lavage solution, high-resolution video colonoscopy and indigocarmine spraying were performed to detect flat lesions. All lesions suggesting neoplastic change were removed by polypectomy or surgery. Cancers invading beyond the submucosal layer were excluded from this analysis. The gross appearance of flat-type lesions was classified as flat elevated type or flat depressed type based on the presence or absence of central depression. Results:A total of 5408 neoplastic lesions were index lesions, including 5035 adenomas and 373 carcinomas (124 with submucosal invasion). The prevalence of flat depressed and flat elevated lesions were 2.8% and 18.1%, respectively. Submucosal invasion rates were 17.1% in the flat depressed, 0.8% in the flat elevated, 1.6% in the sessile, 4.0% in pedunculated lesions and 9.3% in creeping lesions. The submucosal invasion rate in the flat depressed lesions was significantly higher than in any others, except for creeping lesions (P = 0.06). The percentage of flat elevated and flat depressed carcinomas among all carcinomas invading the submucosa was 6.5% and 21.0%, respectively. Conclusion: Flat lesions were common during routine colonoscopy. One-quarter of colorectal cancers may be derived from flat lesions. Training in dye spray technique may result in a higher detection rate of flat colonic lesions.

Pancreatic ductal carcinoma (PDC) is one of the most intractable human malignancies. Surgical resection of PDC at curable stages is hampered by a lack of sensitive and reliable detection methods. Given that DNA microarray analysis allows the expression of thousands of genes to be monitored simultaneously, it offers a potentially suitable approach to the identification of molecular markers for the clinical diagnosis of PDC. However, a simple comparison between the transcriptomes of normal and cancerous pancreatic tissue is likely to yield misleading pseudopositive data that reflect mainly the different cellular compositions of the specimens. Indeed, a microarray comparison of normal and cancerous tissue identified the INSULIN gene as one of the genes whose expression was most specific to normal tissue. To eliminate such a "population-shift" effect, the pancreatic ductal epithelial cells were purified by MUC1-based affinity chromatography from pancreatic juice isolated from both healthy individuals and PDC patients. Analysis of these background-matched samples with DNA microarrays representing 3456 human genes resulted in the identification of candidate genes for PDC-specific markers, including those for AC133 and carcinoembryonic antigen-related cell adhesion molecule 7 (CEACAM7). Specific expression of these genes in the ductal cells of the patients with PDC was confirmed by quantitative real-time polymerase chain reaction analysis. Microarray analysis with purified pancreatic ductal cells has thus provided a basis for the development of a sensitive method for the detection of PDC that relies on pancreatic juice, which is routinely obtained in the clinical setting.

An 18 cm x 16 cm x 10 cm tumor of the stomach, invading the left lobe of the liver, pancreatic body and tail, and transverse colon, with peritoneal deposits on the major omentum, was resected by total gastrectomy plus left hepatic lobectomy, transverse colectomy, distal pancreatectomy, splenectomy, and omentectomy. Histopathologically, the tumor consisted of large uniform cells with significant nuclear atypia, showing solid growth patterns with occasional small nests without adenocarcinoma components. Immunohistochemical investigations of the neoplastic cells confirmed the tumor as a neuroendocrine (NE) carcinoma. molecular analyses disclosed loss of heterozygosity at the MEN1 gene locus on chromosome 11q13. Recurrence occurred at the hepatic hilus and incurred obstructive jaundice 2 months after surgery. Following percutaneous transhepatic biliary drainage, intensive chemotherapy (20 mg/m(2) cisplatin on days 1-5 div, 100 mg/m(2) etoposide on days 1, 3, and 5 div, and 800 mg/m(2) 5-fluorouracil on days 1-5 bolus iv) was started. The recurrent tumor shrank dramatically, and could not be detected on image modalities after five courses of chemotherapy. The patient was well and free of symptoms without biliary drainage for 5 months. Then he began to present with jaundice again, and died of acute massive dissemination 7 months after surgery. An aggressive form of NE carcinoma has been known to be associated with an extremely poor prognosis. However, it is notable that treatment with extensive surgery and intensive chemotherapy could contribute to an improvement in quality of life even if the beneficial effect lasted for only half a year.

This case report describes a 68-year-old man who presented with bronchiolitis obliterans organizing pneumonia (BOOP) and gastric carcinoma. During evaluation, including a colonoscopy, he was found to have distal colitis and a giant polypoid lesion in the cecum that was diagnosed as localized giant inflammatory polyposis (LGIP) by magnifying colonoscopy. The patient was treated over a period of 3 years without surgery, and the LGIP was reduced in size during the follow-up period. Magnifying observation was useful to distinguish LGIP from a neoplastic lesion.

内視鏡切除の対象となる大腸sm癌は,明らかな脈管浸潤がないこと,癌先進部も含めて低分化腺癌でないこと,1,000μmを越える癌浸潤がないこと,のすべてを満たす必要がある.大腸sm癌の内視鏡切除後における追加腸管切除の適応基準としては,癌浸潤距離を1,000μm程度まで引き上げることが可能と考えられ,リンパ管侵襲の判定基準を厳格にすることによっても追加腸管切除例を安全に減らすことも可能と考えられた.従来は内視鏡切除の対象とは考えられなかったsm癌に対する適応拡大を図るためには,リンパ節転移のない大腸sm癌を的確に診断することが必要で,明らかな脈管侵襲や癌先進部の低分化腺癌は内視鏡切除前に診断することは困難であるため,1,000μm以下の癌浸潤を示すsm癌を鑑別する内視鏡診断学の確立が急務である.著者の検討では,表面凹凸不整像や出血の内視鏡所見から鑑別可能であった.

A 58-year old woman was admitted to our hospital complaining of abdominal distension, leg edema and 10 kg weight increase for a month. Abdominal ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI) revealed a heterogeneous giant tumor in the abdomen. Angiography showed some hypervascular lesions supplied by the gastroepiploic arteries. An operation was performed under the diagnosis of an omental malignant tumor. The tumor, which originated from the greater omentum, was resected with a block of the greater omentum. The resected tumor measured 32 x 26 x 13cm and weighed about 6,900g. The histopathological diagnosis was mixed type liposarcoma (myxoid type and round cell type). Three months after the operation, local recurrence was detected. We performed a second operation, but found extensive peritoneal dissemination. About one month later the patient dead.