Biomedical subjects

M Watatani

Publications and source records attributed to M Watatani.

At least 19 recordsLinked to original sources

PubMed2001

Alterations of the double-strand break repair gene MRE11 in cancer.

MRE11 plays a role in DNA double-strand break repair. Hypomorphic mutations of MRE11 have been demonstrated in ataxia-telangiectasia (AT)-like disorder. ATM mutations play a causal role in AT and have been demonstrated in lymphoid malignancies in patients without AT histories. By analogy with the relationship of ATM to lymphoid malignancies, it is probable that alterations of MRE11 are associated with tumor formation. We performed a mutation analysis of MRE11 in 159 unselected primary tumors. Three missense mutations at conserved positions were found in breast and lymphoid tumors. Additionally, an aberrant transcript without genomic mutation was found in a breast tumor. These findings suggest an occasional role for MRE11 alterations in the development of primary tumors.

Alternative Splicing↗

PubMed2001

The potential clinical value of GML and the p53 gene as a predictor of chemosensitivity for colorectal cancer.

BACKGROUND: Adjuvant chemotherapy with 5-fluorouracil (5-FU) and mitomycin C (MMC) has commonly been used after resection of colorectal cancer. The aim of this study was to determine the predictive value of p53 mutation or the expression of GML, a target of p53, for sensitivity to 5-FU and MMC. METHODS: We analyzed p53 mutations and the expression of GML in six colorectal cancer cell lines (SW837, DLD-1, RPMI4788, WiDr, HT-29, and HCT116), and examined the correlation between genetic changes and in-vitro chemosensitivity to MMC and 5-FU by measuring the colony-forming ability in these cell lines. We also introduced GML cDNA into a cell line that lacked endogenous GML expression to investigate changes in sensitivity to MMC and 5-FU. RESULTS: The sensitivity to MMC was highest in HCT116, which had no p53 gene abnormalities and expressed endogenous GML, and lowest in RPMI4788 cells, which had neither p53 gene abnormalities nor expression of endogenous GML. For 5-FU treatment with 24-h exposure, HCT116 showed the highest sensitivity, and SW837, which had p53 mutations without expression of GML, showed the lowest sensitivity. The introduction of GML cDNA to RPMI4788 (RPMI4788-GML) showed that the sensitivity of RPMI4788-GML to MMC was enhanced almost to the level of HCT116 cells. However, when RPMI4788-GML were exposed to 5-FU for 24 h, the sensitivity of RPMI4788-GML was slightly increased compared with that of the parental cells, but was slightly lower than that of HCT116. CONCLUSION: GML expression and p53 mutation in colorectal cancer may be useful predictive genetic markers for sensitivity to MMC and 5-FU, respectively.

Antibiotics, Antineoplastic↗

PubMed2000

Detection of chromosomal aneusomy by fluorescence in situ hybridization in fine-needle aspirates from breast tumors: application to the preoperative diagnosis of breast carcinoma.

BACKGROUND: The authors studied the clinical usefulness of fluorescence in situ hybridization (FISH) analysis of a numerical aberration of chromosomes (aneusomy) using fine-needle aspiration (FNA) samples from patients with breast tumors in the preoperative diagnosis of breast carcinoma. METHODS: FNA samples were obtained from 176 breast tumors and were subjected to conventional cytology and FISH analysis using the centromere probes for chromosomes 1, 11, and 17. Patients with FNA samples that showed aneusomy in at least one of the three chromosomes were diagnosed as positive. RESULTS: Histologic examination revealed 157 malignancies and 19 benign results (10 fibroadenomas, 6 intraductal papillomas, 1 intracystic papilloma, and 2 ADH). The sensitivity, specificity, and diagnostic accuracy were 85.4%, 94.7%, and 86.4%, respectively, for cytology and 90.4%, 100%, and 91.5%, respectively, for FISH. Of 15 breast malignancies that were diagnosed with indeterminate cytology, 13 were diagnosed as positive with FISH analysis (sensitivity, 86.7%). CONCLUSIONS: The results demonstrate that the use of FISH in the diagnosis of FNA samples has a diagnostic accuracy comparable to conventional cytology and is useful in making a definitive diagnosis of malignancy (100% specificity) in patients with indeterminate cytologic results, suggesting that FISH diagnosis can be a good adjunct to conventional cytology.

Adult↗

PubMed2000

Identification of high-risk breast cancer patients from genetic changes of their tumors.

To identify the genetic prognostic markers for breast cancer, we analyzed loss of heterozygosity (LOH) at 11p, 16q, 17p, 17q, and 18q, as well as amplification of the ERBB2, INT2, and MYC genes, in 131 patients with breast carcinoma, 49 of whom had lymph node involvement, but none of whom had distant metastases. Among the several chromosome arms tested, LOH at 17q was correlated with lymph node metastasis. Amplification of the ERBB2, MYC, and INT2 genes was found more frequently in tumors from patients with lymph node metastases than in tumors from those without lymph node metastases. Univariate analysis demonstrated that LOH at 17q and INT2 amplification were factors influencing disease-free survival (DFS). A multivariate analysis was performed on 89 tumors that were able to be evaluated for both LOH at 17q and INT2 amplification, and the results showed that patients who had tumors with these genetic changes were more likely to have a poor prognosis. The findings of this study suggest that investigating genetic changes, in addition to conventional clinicopathologic factors, may contribute to defining groups of breast cancer patients with differences in prognosis.

Blotting, Southern↗

PubMed1999

Mutations of a novel human RAD54 homologue, RAD54B, in primary cancer.

Association of breast tumor susceptibility gene products BRCA1 and BRCA2 with the RAD51 recombination protein suggested that cancer could arise through defects in recombination. The identification of NBS1, responsible for Nijmegen breakage syndrome, from the MRE11/RAD50 recombination protein complex also supports this hypothesis. However, our mutation analysis revealed that known members of the RAD52 epistasis group are rarely mutated in human primary cancer. Here we describe the isolation of a novel member of the SNF2 superfamily, characterized with sequence motifs similar to those in DNA and RNA helicases. The gene, designated RAD54B, is significantly homologous to the RAD54 recombination gene. The expression of RAD54B was high in testis and spleen, which are active in meiotic and mitotic recombination. These findings suggest that RAD54B may play an active role in recombination processes in concert with other members of the RAD52 epistasis group. RAD54B maps to human chromosome 8q21.3-q22 in a region associated with cancer-related chromosomal abnormalities. Homozygous mutations at highly conserved positions of RAD54B were observed in human primary lymphoma and colon cancer. These findings suggest that some cancers arise through alterations of the RAD54B function.

Adenocarcinoma↗

PubMed1999

Mutations in the RAD54 recombination gene in primary cancers.

Association of a recombinational repair protein RAD51 with tumor suppressors BRCA1 and BRCA2 suggests that defects in homologous recombination are responsible for tumor formation. Also recent findings that a protein associated with the MRE11/RAD50 repair complex is mutated in Nijmegen breakage syndrome characterized by increased cancer incidence and ionizing radiation sensitivity strongly support this idea. However, the direct roles of BRCA proteins and the protein responsible for NBS in recombinational repair are not clear though they are associated with the recombinational repair complexes. Since RAD51 forms a complex with other members of the RAD52 epistasis group and with BRCA proteins, it is reasonable to ask if alterations of members of the RAD52 epistasis group lead to tumor development. Here we describe missense mutations at functional regions of RAD54 and the absence of the wild-type RAD54 expression resulting from aberrant splicing in primary cancers. Since RAD54 is a recombinational protein associated with RAD51, this is the first genetic evidence that cancer arises from a defect in repair processes involving homologous recombination.

Adenocarcinoma↗

PubMed1999

Comparison of p53 and bcl-2 expression in initial, synchronous, and metachronous colorectal adenomas.

To investigate the significance of p53 and bcl-2 expression in metachronous colorectal adenomas arising in the remaining colon after carcinoma resection, we analyzed p53 and bcl-2 expression immunohistochemically in initial adenomas (type I), synchronous adenomas with concurrent carcinoma (type II), and metachronous adenomas arising after resection of initial adenomas (type III) or carcinoma (type IV). The incidence of p53 immunoreactivity in type IV adenomas with mild dysplasia was significantly higher than that in type I, type II, or type III adenomas with mild dysplasia. bcl-2 immunoreactivity was more frequently detected in type IV adenomas with mild dysplasia than in type I or type III adenomas with mild dysplasia. Coexpression of p53 and bcl-2 was detected in 16% of the type IV adenomas, this being a significantly higher frequency than that seen in the type I, type II, or type III adenomas. These results suggest that the evaluation of p53 and bcl-2 in metachronous adenomas in the remaining colon after resection of carcinoma may be a useful biologic marker for assessing the risk of cancer development.

Adenoma↗

PubMed1999

Induction of apoptosis in T98G glioblastoma cells by transfection of GML, a p53 target gene.

Expression of the glycosyl-phosphatidylinositol-anchored molecule-like protein (GML) gene, a p53 target, correlates with the sensitivity of some cancer cell lines to anticancer drugs and ionizing radiation. To investigate the function of GML further, we introduced the GML cDNA into various cancer cell lines under control of the tetracycline-regulated system. When we introduced GML into human glioblastoma cell line T98G, which lacks wild-type p53 and expresses no endogenous GML, we observed significant growth suppression accompanied by G2/M arrest in two independent, stable cell lines. We confirmed induction of apoptosis by fluorescence-activated cell sorting (FACS) analysis and nuclear staining. Our results indicated that GML could induce apoptosis of T98G without functional p53, and implied that GML plays a crucial role in the apoptotic pathway in some cancer cells.

Apoptosis↗

PubMed1999

[Detection of numerical aberrations in chromosomes by fluorescence in situ hybridization in fine needle aspirates in the preoperative diagnosis of cancer].

Fine needle aspiration (FNA) samples were obtained from 176 breast tumors suspected of malignancy, which were then subjected to conventional cytological and fluorescence in situ hybridization (FISH) analyses using the centromeric probes for chromosomes 1, 11, and 17. Histological examination revealed 157 breast cancers and 19 benign diseases (ten fibroadenomas, six intraductal papillomas, one intracystic papilloma, and two ADH). Sensitivity, specificity, and diagnostic accuracy were 85.4% 94.7%, and 86.4%, respectively, for cytology and 90.4%, 100%, and 91.5%, respectively, for FISH. These results demonstrate that FISH diagnosis of FNA samples has a diagnostic accuracy comparable to that of conventional cytology.

Biopsy, Needle↗

PubMed1998

Localization of the gene responsible for Peutz-Jeghers syndrome within a 6-cM region of chromosome 19p13.3.

Patients with Peutz-Jeghers syndrome (PJS), an autosomal dominant disease characterized by hamartomatous polyposis of the gastrointestinal tract, are thought to be predisposed to malignancies of the digestive tract, genital tract, and other organs. Using microsatellite markers on chromosome 19p, we have closely defined the region containing the gene responsible for this disorder through linkage analysis in seven affected families. The lack of obligate recombinants at two of these loci, D19S883 and D19S878, with maximum LOD scores of 2.88 and 3.75, confirmed the localization of the PJS locus to chromosome 19. Furthermore, haplotype analysis placed the PJS locus within a 6-cM telomeric region of chromosome 19p, between D19S886 and D19S565.

Centromere↗

PubMed1998

Nine novel germline mutations of STK11 in ten families with Peutz-Jeghers syndrome.

Peutz-Jeghers Syndrome (PJS) is an autosomal dominant hereditary disease characterized by hamartomatous polyposis involving the entire bowel. Recently STK11, a gene bearing a mutation responsible for PJS, was isolated. We investigated the entire coding region of STK11 in 15 unrelated PJS families by the PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) method and PCR-direct sequence analysis, and found nine different, novel mutations among ten of those families. One nonsense mutation and five different frameshift mutations (two families carried the same mutation), all of which would cause truncation of the gene product, were found in seven families; mutations found in five families were clustered within exon 6. Among these five mutations, three occurred at the mononucleotide-repeat region (CCCCCC) of codons 279-281, suggesting that this region is likely to be a mutational hotspot of this gene. One of the remaining three families carried a 3-bp in-frame deletion that would eliminate an asparagine residue within a kinase domain of the product; the other two carried intronic mutations at or adjacent to the consensus dinucleotide sequences of splice-acceptor or -donor sites, which were likely to lead to aberrant splicing.

AMP-Activated Protein Kinase Kinases↗

PubMed1998

An evaluation of neural invasion in esophageal cancer.

It is well known that the operative results for esophageal cancer, especially thoracic esophageal cancer, are not favorable. We analyzed the relationship between neural invasion (NI) and histopathologic factors and recurrence types in 104 patients who underwent resection of esophageal cancers with T2 or greater depth of invasion of the esophageal wall. The implications of NI as a prognostic indicator were also examined. Of the 104 patients, 48 (46.2%) were NI-positive (NI(+)) and 56 (53.8%) were NI-negative (NI(-)). The NI(+) patients had a higher ratio of type 3 cancer. Concerning the histopathologic factors, there was a significant relationship between NI and lymph node metastasis (N) and between NI and lymphatic vessel invasion (ly) (P < 0.05). Examining the types of recurrence, namely hematogenous, lymphogenous, and local/stump, as well as pleural or peritoneal dissemination, a relationship was observed between lymphogenous recurrence and N or ly, and between local/stump recurrence and NI. The prognosis of the NI(+) patients was significantly different from that of the NI(-) patients. According to a multivariate analysis, NI and N were significant prognostic factors. These findings demonstrate that NI is an important prognostic factor closely related to local recurrence in patients with esophageal cancer. Thus, when treating advanced esophageal cancer with T2 or greater depth of invasion, NI and lymph node excision should be considered.

Aged↗

PubMed1998

Infrequent mutations in the PTEN/MMAC1 gene among primary breast cancers.

Recently PTEN/MMAC1, a candidate tumor suppressor gene, was isolated from chromosome 10q23-24 and somatic mutations of this gene were detected in several malignancies including brain, prostate, and breast tumors. To investigate further the potential role of this gene in mammary carcinogenesis, we examined 69 primary breast cancers for mutations in PTEN/MMAC1 by means of polymerase chain reaction single-strand conformation polymorphism and sequencing analysis. We detected only one somatic missense mutation, a change from T to C at codon 59 (TCA to CCA) resulting in substitution of Pro for Ser in the predicted protein. This site is located outside of phosphatase or phosphate-acceptor motifs, but this codon encodes a residue that is conserved in homologous proteins, tensin and auxilin and is likely to be crucial for normal function of PTEN/MMAC1. Among the 69 tumors examined, three low-frequency polymorphisms were found as well, one in the non-coding region of exon 1 and one each in introns 2 and 7. Our results suggested that mutation of the PTEN/MMAC1 gene is not a major factor in the development of most primary breast cancers.

Adult↗

PubMed1997

The importance of neural invasion (NI) as a prognostic factor in diffuse invasive gastric cancer.

The relationship between histological factors, including neural invasion (NI), and survival rates in patients with Borrmann type IV diffuse invasive gastric cancer was examined to determine the significance of NI as a prognostic factor. NI was studied histochemically in 75 patients who underwent resection after 1982, 37 of whom underwent curative resection. The 3-year and 5-year survival rates of the 37 patients who underwent curative resection were 37.2% and 12.7%, respectively. Recurrence was detected as peritoneal dissemination in 19 of those patients (82.6%), and the most significant prognostic factor was the depth of wall invasion (P < 0.01). While NI (P = 0.06) and lymph node metastasis (P = 0.09) appeared to be prognostic factors, there were no significant differences. Therefore, the depth of wall invasion was classified as T2 and T3 or 4 to examine the association of NI and lymph node metastasis with prognosis, whereby NI was shown to be a significant prognostic factor in T2. In conclusion, NI may be a significant prognostic factor in patients with wall invasion of T2 without serosal invasion, as it provides a pathway for the progression to peritoneal dissemination.

Disease Progression↗

PubMed1996

Allelic loss of chromosome 17p, mutation of the p53 gene, and microsatellite instability in right- and left-sided colorectal cancer.

BACKGROUND: Epidemiologic and genetic studies suggest that cancer of the right and left sides of the bowel arise through different mechanisms. To investigate the molecular mechanisms, allelic loss of chromosome 17p, p53 mutations, and microsatellite instability were analyzed in colorectal cancer according to tumor site. METHODS: Using the polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) method, mutations within exons 5-8 of the p53 gene were examined in 108 colorectal cancers including 30 right-sided and 78 left-sided colorectal cancers. Allelic loss of chromosome 17p was studied by restriction fragment length polymorphism analysis, and genetic instability was examined for replication error (RER) at three microsatellite loci on chromosomes 2p, 17p, and 17q. RESULTS: Allelic loss was observed in 61% (14 of 23 informative cases) of right-sided tumors and in 60% (26 of 43 informative cases) of left-sided tumors. PCR-SSCP analysis demonstrated that 63 of 108 tumors had a mutated p53 gene in exons 5, 6, 7, or 8. When comparing the frequency of mutation in each exon based on tumor site, the frequency of mutation in exon 8 in right-sided (2 of 18 informative cases) tumors was significantly lower than that observed in left-sided (17 of 45 informative cases) tumors. RER(+) was observed in 43% of right-sided tumors, whereas 24% of left-sided tumors were RER(+). Although the difference was not statistically significant, a trend was observed between RER(+) phenotype and tumor site. CONCLUSIONS: Our results suggest that the molecular mechanisms of colorectal carcinogens may differ between right- and left-sided tumors.

Alleles↗

PubMed1996

Immunohistochemical analysis of p53 and ras p21 expression in colorectal adenomas and early carcinomas.

To further investigate whether multiple genetic changes are involved in the development of colorectal cancer, we performed an immunohistochemical analysis of p53 and ras p21 protein expression in 139 specimens of colorectal adenoma with varying degrees of dysplasia, 57 specimens of early cancer with an adenomatous component, and 12 specimens of superficial early cancer without any adenomatous component. Positive p53 staining was found in 15% of the adenomas with moderate dysplasia and in 42% of the adenomas with severe dysplasia or intramucosal carcinoma (IMCA). Positive immunostaining of p53 was observed to be significantly correlated with the degree of dysplasia and the depth of invasion, as was the expression of ras p21. However, a closer correlation was observed with the increasing size of the adenomas. Furthermore, p53 staining was positive in 42% of the 12 superficial early cancer specimens, while ras staining was positive in only 1 specimen (8%). These results indicate that p53 gene overexpression may play some biological role in both the adenoma-to-carcinoma sequence and in de novo cancer development, whereas ras p21 expression may not be as involved in de novo cancer development as in the malignant conversion of colorectal adenomas.

Adenomatous Polyps↗

PubMed1996

Second-look operation for recurrent colorectal cancer based on carcinoembryonic antigen and imaging techniques.

PURPOSE: The usefulness of postoperative carcinoembryonic antigen (CEA) monitoring and improvements in imaging techniques have renewed enthusiasm for second-look operations (SLO) as the most effective treatment for recurrent colorectal cancer by reresection following early detection. The aim of our study is to evaluate the role of CEA and imaging techniques-directed SLO. METHODS: Seven hundred fifty-six patients with Dukes Stages B and C, who had undergone curative resection, were monitored postoperatively using CEA and imaging techniques. An SLO was performed on any potentially resectable recurrence, and in addition, an SLO was done when a persistently rising CEA value was detected. RESULTS: Recurrence developed in 18.8 percent (142/756) of patients, and 90.8 percent (129/142) of the recurrences were detected within the first three years following curative resection. When comparing carcinomas of the colon with that of the rectum, the former were associated with significantly more hepatic and intraabdominal recurrences, whereas the latter had significantly more locoregional and pulmonary recurrences. Seventy-two patients underwent SLO. Of these patients, 54.2 percent (39/72) had all of their disease resected, and 1.4 percent (1/72) had no detectable disease at the SLO. Among the 142 patients with recurrence, 71 (50 percent) patients underwent SLO. The resectable group at SLO carried a significantly better survival than the unresectable recurrence group (41.3 vs. 5.2 percent; P<0.01). CONCLUSIONS: Complete removal of colorectal cancer recurrences by SLO, on the basis of postoperative, follow-up CEA and imaging technique findings, results in improved survival.

Actuarial Analysis↗

PubMed1996

Variant mutational activation of the K-ras oncogene in renal mesenchymal tumors induced in newborn F344 rats by methyl(methoxymethyl)nitrosamine.

Renal mesenchymal tumors were induced at high incidence in F344 rats by a single intraperitoneal injection of methyl(methoxymethyl)nitrosamine (DMN-OMe) within 48 h after birth. DNAs from 18 of 35 mesenchymal tumors contained transforming ras sequences in NIH3T3 transfection assays: K-ras (17/18) or N-ras (1/18). Single-stranded conformational polymorphism analysis or dideoxy sequencing of polymerase chain reaction-amplified K-ras gene fragments revealed that these neoplasms contained a variety of activating mutations in the K-ras oncogene. Alterations in codon 12 predominated and included GGT --> GAT transitions, GGT --> GTT or TGT transversions, and previously reported insertion mutations, although some tumors expressed more than one mutation and the pattern of mutations even varied within tumors. Mutations were also found in exons 2 and 3. In addition, tumor transplantability into syngeneic hosts correlated positively and significantly with K-ras activation. Renal mesenchymal tumors with transforming mutations in exon 1 were often successfully passaged (10/12) while tumors which lacked mutations in exon 1 were infrequently transplantable (2/14). While the observed base substitutions in K-ras are consistent with adduct formation, the presence of insertion mutations and intratumor heterogeneity of alterations suggest that ras activation in DMN-OMe-induced tumors is not necessarily an early event in tumorigenesis.

Animals↗