Biomedical subjects

K Aozasa

Publications and source records attributed to K Aozasa.

At least 19 recordsLinked to original sources

PubMed2000

Sequences of cytotoxic T-lymphocyte epitopes in the Epstein-Barr virus (EBV) nuclear antigen-3B gene in a Japanese population with or without EBV-positive lymphoid malignancies.

Latent infection antigens of EBV, including EBV nuclear antigens (EBNAs) and latent membrane proteins, are expressed in latently infected and immortalized B cells but work as target antigens for host cytotoxic T-lymphocyte (CTL) responses in an HLA class I-restricted manner. Among these latent antigens, the immunodominant CTL epitopes in EBNA3B (EBNA3B 399-408 and EBNA3B 416-424) are well characterized. Mutations and strain differences in these sequences, compared to the prototype A sequence, reduce CTL responses to latently infected B cells. These EBNA3B CTL epitopes in the normal Japanese population and in 2 lymphoid neoplasias, pyothorax-associated lymphoma (PAL) and nasal natural killer-cell lymphoma, were directly sequenced by PCR. Most EBV in peripheral blood leukocytes (PBLs) from healthy Japanese donors exhibited the prototype A sequence, with mutations in approximately 20% (3/16). The sequence of EBNA3B CTL epitopes in lymphoma tissue was obtained in 6 PAL cases, and 5 exhibited mutations or strain differences compared to the prototype A sequence. Furthermore, the EBNA3B sequence in PAL tissue was different from that in PBLs of the same patient or 1 of the sequences found in PBLs. However, the EBNA3B gene in nasal lymphoma tissues exhibited predominantly the prototype A sequence. Because PAL cells expressed EBNA3B mRNA, detected by RT-PCR, but nasal lymphoma cells did not, mutations and strain differences of the sequences of EBNA3B CTL epitopes were specific findings in EBNA3B-positive lymphomas.

Adult↗

PubMed2000

Low frequency of HLA-A*0201 allele in patients with Epstein-Barr virus-positive nasal lymphomas with polymorphic reticulosis morphology.

Lymphoproliferative diseases of the nasal cavity and paranasal sinuses occur frequently in Asian countries and are histologically categorized as monomorphic ordinary lymphoma and polymorphic reticulosis (PR) with apparent inflammatory cell infiltration. The large atypical cells in PR show natural-killer cell nature and frequently contain Epstein-Barr virus (EBV) DNA. Among the EBV genes involved in latent infection, those encoding EBV latent membrane proteins are frequently expressed in PR. Several cytotoxic T-lymphocyte (CTL) defined epitopes have been mapped to latent membrane proteins restricted with HLA-A2, -A11 or -A24 antigens. Thus, the HLA-A allele may affect the development of PR. To examine this possibility, HLA-A alleles of 25 patients with EBV(+) PR were determined with low-resolution polymerase chain reaction-based typing using HLA-A locus sequence-specific primer combinations. The frequency of HLA-A alleles including HLA-A2 and -A24 antigens in PR patients was lower than that in the normal Japanese population, but the difference was not significant. Since HLA-A2-restricted CTL responses are well delineated at the A2-subtype level, the A2-subtype of PR cases with HLA-A2 antigen was further determined by high-resolution genetic typing. The frequency of HLA-A*0201 in PR was significantly lower than in the normal population (p=0.0314). The HLA-A*0201-restricted CTL responses may thus function in vivo to suppress the development of overt lymphoma.

Adult↗

PubMed2000

Specific c-kit mutations in sinonasal natural killer/T-cell lymphoma in China and Japan.

Sinonasal lymphoma is one of the constituents of lethal midline granuloma, which is a clinical term for progressive, destructive lesions affecting the midline of the face. The majority of sinonasal lymphomas, especially those showing polymorphous patterns of proliferation and thus termed polymorphic reticulosis, recently were categorized as sinonasal natural killer/T-cell lymphomas. They are more prevalent in Asia than Europe or North America and are associated with EBV infection. Twenty-three cases with sinonasal natural killer/T-cell lymphomas were collected from two high-incidence regions: Beijing, China (14 cases) and Osaka, Japan (9 cases). c-kit mutations were analyzed on paraffin-embedded specimens by PCR-single-strand conformation polymorphism followed by direct sequencing; the c-kit proto-oncogene encodes a receptor of tyrosine kinase, which plays an important role in the regulation of normal and neoplastic hematopoiesis by the interaction with its specific ligand, termed stem cell factor. Twelve single nucleotide substitution mutations were seen in 23 cases. Ten of 14 Chinese cases (71.4%) had mutations at exon 11 or exon 17, whereas only two of nine Japanese cases (22.2%) had mutations, showing a significant difference in frequency between Chinese and Japanese cases. Furthermore, seven of eight mutations (92%) in exon 17 occurred at codon 825 and three of four mutations (75%) in exon 11 occurred at codon 561. Such a specificity has not been reported before, and these results, taken together, suggest that location-specific differences in etiological factors cause specific mutations in c-kit gene.

Adolescent↗

PubMed2000

Cancer immunotherapy targeting Wilms' tumor gene WT1 product.

The Wilms' tumor gene WT1 is expressed at high levels not only in acute myelocytic and lymphocytic leukemia and in chronic myelocytic leukemia but also in various types of solid tumors including lung cancers. To determine whether the WT1 protein can serve as a target Ag for tumor-specific immunity, three 9-mer WT1 peptides (Db126, Db221, and Db235), which contain H-2Db-binding anchor motifs and have a comparatively higher binding affinity for H-2Db molecules, were tested in mice (C57BL/6, H-2Db) for in vivo induction of CTLs directed against these WT1 peptides. Only one peptide, Db126, with the highest binding affinity for H-2Db molecules induced vigorous CTL responses. The CTLs specifically lysed not only Db126-pulsed target cells dependently upon Db126 concentrations but also WT1-expressing tumor cells in an H-2Db-restricted manner. The sensitizing activity to the Db126-specific CTLs was recovered from the cell extract of WT1-expressing tumor cells targeted by the CTLs in the same retention time as that needed for the synthetic Db126 peptide in RP-HPLC, indicating that the Db126-specific CTLs recognize the Db126 peptide to kill WT1-expressing target cells. Furthermore, mice immunized with the Db126 peptide rejected challenges by WT1-expressing tumor cells and survived for a long time with no signs of autoaggression by the CTLs. Thus, the WT1 protein was identified as a novel tumor Ag. Immunotherapy targeting the WT1 protein should find clinical application for various types of human cancers.

Animals↗

PubMed2000

Extent and zonal distribution of prostatic intraepithelial neoplasia in patients with prostatic carcinoma in Japan: analysis of whole-mounted prostatectomy specimens.

BACKGROUND: Prostatic intraepithelial neoplasia (PIN), an intraluminar proliferation of epithelial cells in ducts and acini, is divided into high-grade (HGPIN) and low-grade (LGPIN), based on morphologies. HGPIN is considered to be a putative precursor of prostatic adenocarcinoma (PCA). Information on PIN has been limited in Japan, because PIN had not been regarded as a precursor lesion for PCA. METHODS: In this study, extent and zonal distribution of PIN together with its relationship with PCA were examined in totally embedded radical prostatectomy specimens obtained from 70 patients with PCA. Fifty-three patients received androgen deprivation therapy (castrated) and remaining 17 did not (noncastrated). RESULTS: Frequency of HGPIN in noncastrated cases (76%) was much higher than that in castrated cases (26%) (P < 0.001). LGPIN showed the same tendency, but the difference was smaller. Difference in mean number of HGPIN in noncastrated and castrated cases (12.0 and 6.4, respectively) was more marked than in LGPIN (6.4 and 5.1, respectively). Reduction rate of mean size in HGPIN (26%) by the androgen deprivation therapy was larger than in LGPIN. When evaluated in noncastrated cases, the coexistence of PCA and HGPIN was found in 76% of cases in the nontransition and 53% in the transition zone. Close association of PCA and PIN (</=2 mm distance between lesions) was more frequently found in HGPIN (55% of lesions) than in LGPIN (37%) (P < 0.05). Frequency of close association of HGPIN with PCA was 65% in the nontransition and 35% in transition zone. CONCLUSIONS: The present study from Japan supports the etiological importance of HGPIN in the development of PCA. The effect of androgen deprivation therapy is much more marked in HGPIN than in LGPIN.

Adenocarcinoma↗

PubMed2000

Epstein-Barr virus associated B-cell lymphoma of brain developing in myelodysplastic syndrome with c-kit mutation (Try-557 -->stop).

The first case of B-cell lymphoma of brain in a patient with myelodysplastic syndrome (MDS) was reported. A 68-year-old man was admitted because of anemia, fever, and thrombocytopenia and was diagnosed as having MDS (refractory anemia with excess of blasts) on the basis of the findings of bone marrow aspiration and chromosomal analysis. The patient was followed up without chemotherapy, but a brain tumor appeared after 3 years. Histologic and immunohistologic examinations revealed diffuse large B-cell lymphoma. Mutations of the c-kit proto-oncogene (stem cell factor receptor) and the p53 tumor-suppressor gene were examined in the MDS lesion and malignant lymphoma (ML) by the polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) method followed by direct sequencing. The p53 mutation was not found in either MDS or ML, but a nonsense mutation (Try-557 --> stop) in exon 11 of the c-kit, which might lead to dysfunction of tyrosine kinase activity, was detected in MDS. This is the first report of c-kit mutation in MDS. Epstein-Barr virus (EBV) genome was demonstrated in the nucleus of brain ML cells by in situ hybridization with EBV-encoded RNA-1 probe. Immunohistochemistry showed that the tumor cells expressed latent infection gene products, including EBV nuclear antigen-2 and latent membrane protein-1. This pattern of latent gene expression was Lat III, which is usually found in malignant lymphomas developing in immunocompromised hosts. These findings suggest that a profound pancytopenia in MDS resulted in an immunodeficient condition, after which EBV-positive B-cell lymphoma of brain developed.

Aged↗

PubMed2000

Cytotoxic T-lymphocyte responses elicited to Wilms' tumor gene WT1 product by DNA vaccination.

We recently have reported that Wilms' tumor gene WT1 is highly expressed not only in leukemias but also in various types of solid tumors and that WT1 protein is a novel tumor antigen against which cytotoxic T lymphocytes (CTLs) can be elicited by immunization with 9-mer WT1 peptides capable of binding to major histocompatibility complex (MHC) class I molecules. In the present study, plasmid DNA encoding murine full-length WT1 protein was injected intramuscularly into C57BL/6 mice. The mice vaccinated with the WT1 plasmid DNA elicited CTLs against the WT1 protein, and the CTLs specifically killed WT1-expressing tumor cells in a MHC class I-restricted manner. Furthermore, the vaccinated mice rejected the challenges of WT1-expressing tumor cells and survived with no signs of autoimmunity caused by the CTLs. These results demonstrated that vaccination with the WT1 plasmid DNA can elicit CTL responses specific for the WT1 protein, resulting in the acquisition of rejection activity against challenges of WT1-expressing tumor cells. This WT1 DNA vaccination may find clinical application for various types of solid tumors as well as leukemias.

Animals↗

PubMed2000

Mutations of the p53 gene in nasal NK/T-cell lymphoma.

Mutations of the p53 tumor suppressor gene are reported in various kinds of malignancies including lymphomas. However, p53 gene mutations in nasal NK/T-cell lymphoma have not been reported because most parts of tumors are necrotic and a small amount of living tumor tissues is available for the molecular study. Expression and mutations of the p53 gene were examined in the paraffin-embedded specimens of the nasal lesions from 42 Chinese (Beijing and Chengdu) and Japanese (Okinawa and Osaka) patients with nasal NK/T-cell lymphoma by the immunohistochemistry and single strand conformation polymorphism (SSCP) analysis of polymerase chain reaction (PCR) amplified products followed by direct sequencing. Thirty single-nucleotide substitution mutations were observed in 20 of 42 cases (47.6%). Among the 30 mutations, 18 were missense (mainly G:C to A:T transitions), 9 were silent, and 1 was a nonsense mutation. The remaining 2 mutations involved intron 5 and exon 5 terminal points. Abnormal expression of the p53 protein was also observed in 19 of 42 (45.2%) cases. The incidence was significantly (4-fold) higher in the cases of Osaka than those in other areas, although the incidence of p53 mutations in the cases of Osaka was one-half to one-third of those in the other three areas. The results may suggest some racial, environmental, or lifestyle differences in the cause of nasal tumorigenesis.

Adult↗

PubMed2000

Induction of chromosomal aberrations and growth-transformation of lymphoblastoid cell lines by inhibition of reactive oxygen species-induced apoptosis with interleukin-6.

Etiological evidence, indicating the relationships between the onset of malignant lymphoma and pre-existing chronic inflammation, has been accumulated. For the autonomous growth of malignant tumor, genetic lesions, such as chromosomal aberrations, amplification of oncogenes, and mutations of genes involved in the cell cycle regulation, must be essential. However, how the inflammation promotes the accumulation of genetic lesions and induces the autonomous growth of lymphoid cells remains unclear. Reactive oxygen species released by polymorphonuclear leukocytes and macrophages are factors causing DNA damage in the foci of inflammation, and thus could play a role in lymphomagenesis. The xanthine/xanthine oxidase (X/XOD) system produces a mixture of hydrogen peroxide and superoxide anion extracellularly, and thus serves as an in vitro source of reactive oxygen species. Cell death of lymphoblastoid cell lines (LCLs) was induced with X/XOD treatment in a dose-dependent manner. DNA fragmentation, which is the characteristic feature of apoptosis, was observed in LCLs at 4-8 hours after X/XOD treatment. Among cytokines such as interleukin-6 (IL-6), IL-10, and interferon-gamma, only pretreatment with IL-6 gave LCLs the resistance to X/XOD-induced cell death in a dose-dependent manner. The proportion of apoptotic cells in X/XOD-treated LCL culture was decreased with IL-6 pretreatment by quantification with flow cytometric analysis. Treatment of LCLs with IL-6 for 48 hours up-regulated bcl-2 mRNA expression. Furthermore, the LCLs repeatedly treated with X/XOD and cultured with or without IL-6 showed many more structural abnormalities of chromosomes than those without X/XOD treatment. Colony forming efficiency of X/XOD-treated LCLs with IL-6 was significantly higher than those without IL-6, and even relatively higher than LCLs without X/XOD treatment. IL-6 could support the survival of non-neoplastic B cells and accelerate the malignant transformation of B lineage cells in inflammatory lesions.

Apoptosis↗

PubMed2000

Expression of interleukin-7 and its receptor in thyroid lymphoma.

Patho-epidemiological studies have shown that thyroid lymphomas (TL) develop in thyroids affected by chronic lymphocytic thyroiditis (CLTH). Cytokines produced in CLTH might play a pivotal role for lymphomagenesis, because previous reports indicate an important role of cytokines in lymphomagenesis. We examined the expression of interleukin-7 (IL-7), a pleiotropic cytokine that acts mainly on cells of the hematolymphoid system, and IL-7 receptor (IL-7R) in both TL and CLTH by RT-PCR. IL-7-specific transcripts were detected more frequently in TL than in CLTH lesions (p < 0.01). IL-7 expression was higher in TL than in CLTH. IL-7R and the common gamma chain were expressed in all but one TL and in all CLTH lesions, in similar levels. We established the sensitive in situ hybridization (ISH) method for detection of IL-7. ISH for IL-7 revealed cytoplasmic signals among cells in the germinal center and mantle zone of lymphoid follicles and interfollicular areas in the TL and CLTH lesions. In the lymphomatous areas of TL, similar numbers of scattered large and small lymphoid cells expressing IL-7 were found. The number of IL-7-expressing cells counted in 10 fields in TL (119.4 +/- 10.6 cells) was significantly higher than found in CLTH lesions (43.1 +/- 4.6) (p < 0.001). These findings suggest a pathogenetic role for IL-7 in the development of TL. ISH showed that the germinal center cells, interfollicular cells, and lymphoma cells expressed IL-7R, but mantle zone cells did not. Because lymphoid cells in lymphoid follicles and the interfollicular area formed in CLTH expressed IL-7, TL cells might proliferate via their own IL-7 and IL-7R, and via IL-7 from reactive lymphoid cells.

Aged↗

PubMed2000

Role of hypermethylation of DAP-kinase CpG island in the development of thyroid lymphoma.

Death-associated protein-kinase (DAP-Kinase) is a serine/threonine kinase with a death domain that is involved in apoptosis induced by interferon-gamma, TNF-alpha, and Fas ligand. Epigenetic down-regulation of DAP-Kinase gene expression by hypermethylation of its promoter region was reported in B-cell malignancies. Previous pathoepidemiologic studies indicated that thyroid lymphoma (TL) evolves among active lymphoid cells in chronic lymphocytic thyroiditis (CLTH). With use of methylation-specific polymerase chain reaction, the methylation status of DAP-Kinase CpG island was examined in thyroid lesions of 19 cases with TL and 9 with CLTH. The frequency of methylation was higher in TL cases (16 of 19, 84.2%) than in CLTH cases (2 of 9, 22.2%) (p < 0.01). DNA extracted from peripheral blood leukocytes from TL and CLTH cases never showed methylation, indicating that the methylation occurred somatically in the lesional lymphocytes in thyroid. These findings suggested that methylation of the DAP-Kinase promoter region might be involved in the development of TL from CLTH.

Adult↗

PubMed2000

Expressions of Fas ligand and other apoptosis-related genes and their prognostic significance in epithelial ovarian neoplasms.

Expression of apoptosis-related proteins, bcl-2, Bax, Fas and Fas ligand (L), in ovarian epithelial neoplasms together with its clinical relevance was examined by immunohistochemistry. They included 36 cases with adenoma, 33 with low potential malignancy (LPM) and 63 with carcinomas. bcl-2 expression was observed in 14 of 36 cases (39%) with adenoma, five of 33 (15%) with LPM (P< 0.05) and 12 of 63 (19%) with carcinoma (P < 0.05). Cases with bcl-2 expression showed more favourable prognosis than those without, but the difference was not statistically significant. There was no difference in frequency of Bax and Fas expression between each histologic category. Fas L expression was observed in one of 36 cases (3%) with adenoma, but in 12 of 33 (36%) with LPM (P < 0.001) and 42 of 63 (67%) with carcinoma (P < 0.0001). In carcinomas, cases expressing Fas L showed a less favourable prognosis than those without (P = 0.02). Density of CD8+ lymphocytes, possibly cytotoxic T-cells, was higher in serous carcinoma with negative Fas L expression than those with positive Fas L expression. These findings suggest that Fas L expressing carcinomas induce apoptosis in infiltrating CTL with Fas expression, and escape from immune surveillance.

Adenoma↗

PubMed2000

Pyruvate secreted by human lymphoid cell lines protects cells from hydrogen peroxide mediated cell death.

Reactive oxygen species (ROS) released from polymorphonuclear leukocytes and macrophages could cause DNA damage, but also induce cell death. Therefore inhibition of cell death must be an important issue for accumulation of genetic changes in lymphoid cells in inflammatory foci. Scavengers in the post culture medium of four lymphoid cell lines, lymphoblastoid cell lines (LCL), Raji, BJAB and Jurkat cells, were examined. Over 80% of cultured cells showed cell death 24 h after xanthine (X)/xanthine oxidase (XOD) treatment, which was suppressed by addition of post culture medium from four cell lines in a dose-dependent manner. H2O2 but not O2*- produced by the X/XOD reaction was responsible for the cytotoxity, thus we used H2O2 as ROS stress thereafter. The H2O2-scavenging activity of post culture media from four cell lines increased rapidly at the first day and continued to increase in the following 2-3 days for LCL, Raji and BJAB cells. The scavenging substance was shown to be pyruvate, with various concentrations in the cultured medium among cell lines. Over 99% of total pyruvate was present in the extracellular media and less than 1% in cells. alpha-Cyano-4-hydroxycinnamate, a specific inhibitor of the H+-monocarbohydrate transporter, increased the H2O2-scavenging activity in the media from all four cell lines via inhibition of pyruvate re-uptake by cultured cells from the media. These findings suggest that lymphoid cells in inflammatory foci could survive even under ROS by producing pyruvate, so that accumulation of lymphoid cells with DNA damage is possible.

Cell Death↗

PubMed2000

Characteristics of cutaneous lymphomas in Osaka, Japan (1988-1999) based on the European Organization for Research and Treatment of Cancer classification.

Based on accumulating information, European investigators proposed a new classification for primary cutaneous lymphomas known as the European Organization for Research and Treatment of Cancer (EORTC) classification. The clinical utility of this classification in Japanese cases has not been evaluated. Material from 65 patients with cutaneous lymphomas (48 with primary disease and 17 with secondary disease) who were admitted to Osaka University Hospital during the period 1988 through 1999 was reviewed. Immunohistochemical analysis was performed in all cases. Cutaneous T-cell lymphoma (CTCL) comprised mycosis fungoides (15 cases), Sézary syndrome (1 case), lymphomatoid papulosis (5 cases), large cell CTCL (13 cases), pleomorphic small- or medium-sized CTCL (2 cases), and cutaneous natural killer /T-cell lymphoma (4 cases). B-cell lymphomas comprised 7 cases of follicle center cell lymphoma and 1 case of diffuse large B-cell lymphoma of the leg. Each category of disease in the EORTC scheme showed its characteristic features in our series. Five of 13 large cell CTCL cases were positive for CD30, and 5 were negative. The 5-year survival rate of patients with large cell CTCL CD30+ disease was 100% and that of patients with CD30- disease was 0%. (p > 0.1). Only 1 of 7 CTCL cases expressing CD30 was ALK-1+, and all 7 cases showed a favorable clinical course. The EORTC classification is effective in dealing with Japanese cases of cutaneous lymphomas.

Adolescent↗

PubMed2000

Interleukin-10 gene transfer improves the survival rate of mice inoculated with Escherichia coli.

OBJECTIVE: To determine whether administration of recombinant adenovirus vectors encoding the interleukin (IL)-10 protein (AxCAmIL-10) decreases the mortality of septic mice. DESIGN: Prospective, randomized, controlled study. SETTING: University research laboratory. SUBJECTS: Adult male C57B/6 mice. INTERVENTIONS: Untreated mice and those injected intraperitoneally with 1 x 10(9) pfu of AxCAmIL-10 were used as control 1 and 2, respectively. Double-capsules without Escherichia coli were intraperitoneally embedded in another group (control 3). Mice embedded with capsules containing E. coli were divided into the following groups: simultaneous administration of 0.5 mL of saline (group 1), and administration of AxCAmIL-10 3 hrs before embedding (group 2) or 1 hr after embedding (group 3). Histopathologic changes together with expression concentrations of IL-10 and tumor necrosis factor (TNF) in various organs and plasma were examined 18 hrs after each treatment. Observation periods were 5-8 days. Survival rates were compared between these groups. MEASUREMENTS AND MAIN RESULTS: The plasma IL-10 concentrations were increased in control 2, group 2, and group 3 but not in control 1, control 3, or group 1, indicating successful adenovirus gene transfer. Plasma TNF values were significantly reduced in groups 2 and 3 as compared with group 1, with no significant differences in endotoxin concentrations. Survival rates were significantly better in groups 2 and 3 than in group 1 (p < .05). CONCLUSION: These findings suggested that IL-10 has a favorable effect on survival of septic mice via inhibition of TNF production or endotoxin stimulation.

Adenoviridae↗

PubMed2000

Analysis of T-cell antigen receptor gamma chain gene rearrangement by polymerase chain reaction in combination with denaturing gradient gel electrophoresis in the differential diagnosis of cutaneous T-lymphoproliferative diseases.

A polymerase chain reaction (PCR)-based strategy has been developed for analysis of clonal rearrangement of the T-cell receptor gamma gene (TCR gamma) and was shown to be useful for detection of clonal T-cell populations. In this study, we performed PCR combined with denaturing gradient gel electrophoresis (DGGE) on fresh frozen biopsy samples from 16 patients with cutaneous T-lymphoproliferative diseases in whom a definite diagnosis was difficult to make on morphological and immunohistochemical grounds alone. Ages of the patients at biopsy ranged from 28 to 81 (median 62) years, and the subjects consisted of 8 men and 8 women. They presented with erythema on the extremities in 5 cases, trunk in 7, buttock in 2, and papules on the trunk and face in one case each. Clonal rearrangement of TCR gamma was observed in 3 of 16 cases. Clinical diagnoses of these three cases were mycosis fungoides, cutaneous invasion of adult T-cell leukemia (ATL), and large granular lymphocytic leukemia (LGL) of T-cell type, respectively, but they were histologically difficult to differentiate from reactive cutaneous T-cell proliferation. The skin lesions of the LGL case worsened, and this patient died two years after biopsy. Another patient with suspected mycosis fungoides in the plaque stage died due to dissemination of tumors 22 months after biopsy. The remaining one patient with ATL survived with cutaneous lesions for over four years. Clonality was not demonstrated in the remaining 13 cases, and their clinical courses were favorable. These findings showed that demonstration of clonal TCR gamma gene rearrangement using the PCR-DGGE method is very helpful for diagnosis of cutaneous T-cell neoplasms.

Adult↗

PubMed2000

Microsatellite instability and k-ras, p53 mutations in thyroid lymphoma.

Patho-epidemiological studies showed that thyroid lymphoma (TL) arises in inflammatory lesions of chronic lymphocytic thyroiditis (CLTH). Replication error (RER) is found in inflammatory lesions and associated cancer, suggesting that chronic inflammation could be a risk factor for neoplastic development through causing RER. To clarify whether RER is involved in the pathogenesis of TL, we examined the microsatellite instability (MSI) in 9 cases with CLTH and 19 with TL, including 10 diffuse large B-cell lymphoma (DLBL), 4 follicle center cell lymphoma, 3 marginal zone B-cell lymphoma of extranodal (MALT) type, and 2 lymphoplasmacytic type. Sixteen distinct microsatellite repeats were analyzed. Mutations of p53 and k-ras genes were also examined. When alterations at 2 or more microsatellite loci were judged as positive, only 5 DLBL cases exhibited MSI. The frequency of MSI in DLBL was significantly higher than that in other types of TL and CLTH (P < 0.05). Four of 19 cases (21.1%) showed point mutation of the k-ras gene. The k-ras mutations occurred in the cases with DLBL with RER, and four of five cases with RER had a k-ras mutation, indicating a close association between RER and k-ras mutation. p53 mutations were not found in the CLTH. Two of 19 TL cases showed mutations of p53 gene. There was no significant association between RER and p53 mutation. These findings indicate that genomic instability contributes to the progression of TL from low grade to high grade, but not to the development of low grade lymphoma in CLTH lesions.

Adult↗

PubMed2000

p53 mutations in prostatic intraepithelial neoplasia and concurrent carcinoma: analysis of laser capture microdissected specimens from non-transition and transition zones.

Prostatic intraepithelial neoplasia (PIN) is characterized by intraluminal proliferation of epithelial cells and is divided into high-grade (HGPIN) and low-grade (LGPIN) lesions. HGPIN is regarded as the most likely precursor of prostatic cancer (PCA). Microdissected DNA selectively extracted from paraffin-embedded sections of 27 cases with PCA were analyzed for p53 mutation in exons 5 - 8 by single-strand conformation polymorphism of polymerase chain reaction-amplified DNA fragments (PCR-SSCP) followed by direct sequencing. These patients received total prostatectomy (27 cases). After a review of histologic sections, DNA was extracted from 193 locations; 111 lesions from 27 cases with HGPIN (75 lesions from non-transition zone and 36 from transition zone), 55 lesions from 27 cases with PCA (30 lesions from non-transition zone and 25 from transition zone), and 27 from 27 benign glands. Analysis revealed 27 mutations of the p53 gene in 24 lesions from 12 cases. Benign glands adjoining PIN and / or PCA had no mutations. All mutations were point mutations: 17 missense, 7 silent, and 2 nonsense. Mutations were detected in 6 cases (22.2%) or 13 of 111 lesions (11.7%) with HGPIN and 8 cases (29.6%) or 11 of 55 lesions (20.0%) with PCA. In a given case, HGPIN and PCA lesions had different p53 mutations from each other, suggesting multiclonal development of prostatic precancerous lesions. The frequency of p53 mutation of PCA was significantly higher in the non-transition zone (33.3%) than in the transition zone (4%), and higher in the stage T3 cases (30.3%) than in the stage T2 cases (4.5%, 1 of 22 lesions) (both P < 0.05). Frequency of p53 mutation of PIN in the non-transition zone (14.7%) was higher than that in the transition zone (5.6%), although the difference was not significant. The frequency rate of p53 mutation in HGPIN close to PCA ( </= 2 mm) was significantly higher (24%) than that in HGPIN lesions > 2 mm from PCA (3%). All these findings indicate that the p53 gene mutations are involved in prostatic carcinogenesis and explain why the non-transition zone is the predominant site of PCA.

Genes, p53↗