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Biomedical subjects

Jae Y Ro

Publications and source records attributed to Jae Y Ro.

At least 55 records · Page 3Linked to original sources
PubMed2003

Treatment of former smokers with 9-cis-retinoic acid reverses loss of retinoic acid receptor-beta expression in the bronchial epithelium: results from a randomized placebo-controlled trial.

BACKGROUND: Loss of retinoic acid receptor beta (RAR-beta) expression in the bronchial epithelium is considered a biomarker of preneoplasia. Retinoids can restore expression of this receptor and, presumably, halt the progression of carcinogenesis. This study was designed to investigate whether either of two retinoid-based regimens, 9-cis-retinoic acid (RA) or 13-cis-RA plus alpha-tocopherol (AT), could reverse RAR-beta expression loss in former smokers after 3 months of treatment. METHODS: Individuals (n = 226) who had smoked at least 20 pack-years and had ceased smoking for at least 12 months were randomly assigned to receive 3 months of daily oral 9-cis-RA (100 mg), 13-cis-RA (1 mg/kg) + AT (1200 IU), or placebo. Bronchoscopy and biopsy at six predetermined sites of the bronchial tree were performed before treatment and at 3 and 6 months thereafter. Specimens were evaluated for squamous metaplasia, dysplasia, and RAR-beta expression. McNemar's test was used to test changes in RAR-beta expression and squamous metaplasia within each treatment group, and a generalized estimating equations model was applied to model the treatment effect, adjusting for covariates. All statistical tests were two-sided. RESULTS: A total of 177 assessable subjects completed at least 3 months of therapy and underwent at least the baseline and 3-month bronchoscopic evaluations with biopsies. RAR-beta was detected in 69.7% of all baseline biopsy samples, and metaplasia was evident in 6.9% of all baseline samples from 240 subjects. Restoration of RAR-beta expression (P =.03) and reduction of metaplasia (P =.01) were found in the 9-cis-RA group. After adjustment for years of smoking, packs/day smoked, and metaplasia, treatment with 9-cis-RA, but not with 13-cis-RA + AT, led to a statistically significant increase in RAR-beta expression compared with placebo (P =.03). CONCLUSION: 9-cis-RA treatment can restore RAR-beta expression in the bronchial epithelium of former smokers, raising the possibility that this retinoid has potential chemopreventive properties in former smokers.

Adult↗
PubMed2003

Triple synchronous neoplasms in one kidney: report of a case and review of the literature.

We report the case of a patient with three synchronous but histologically different primary renal tumors that were all in the same kidney. Two tumors were different subtypes of renal cell carcinoma (RCC), and the third was a variant form of angiomyolipoma. The patient was a 62-year-old man who was receiving antihypertensive drugs and came to our hospital for a regular check-up. Ultrasonography performed during the visit revealed a left renal mass, but the patient had no related symptoms. Subsequent computed tomography revealed two round, high-density masses, one in the mid-portion and the other in the lower pole of the left kidney, and multiple cysts in the right kidney and the liver. The mass in the mid-portion measured 3.3 x 3.0 x 2.8 cm, and the mass in the lower pole measured 1.7 x 1.1 x 0.9 cm. A left radical nephrectomy was performed. On gross examination, an additional ovoid nodule (0.6 cm in the greatest dimension) was found in the lower pole. Microscopically, the largest tumor consisted of a broad alveolar arrangement of large round cells with abundant eosinophilic or clear cytoplasm, distinct cell borders, and perinuclear halos, features consistent with chromophobe RCC. The smallest tumor was a conventional (clear-cell) RCC. The third tumor was composed solely of atypical epithelioid cells with prominent nucleoli and yellowish-brown to black pigments. The tumor cells were positive for melanin (Fontana-Masson stain), the melanoma marker HMB45, vimentin, smooth-muscle actin, and the macrophage marker CD68 and were negative for cytokeratin. This tumor was considered a pigmented epithelioid type of angiomyolipoma. The histologic, histochemical, and immunohistochemical features in this case confirmed the presence of three synchronous primary tumors, a chromophobe and a clear-cell type RCC and a pigmented epithelioid angiomyolipoma, all of which were in the same kidney. This case is the first of its type reported in the literature.

Angiomyolipoma↗
PubMed2003

Basaloid carcinoma of the lung: a really dismal histologic variant?

BACKGROUND: Basaloid carcinoma of the lung has been reported as an uncommon and highly aggressive form of nonsmall cell lung cancers. Even in stage I and II of basaloid carcinoma, a 5-year survival rate of only 15% has been reported and it has been suggested that different treatment modalities for basaloid carcinoma should be considered. The aim of this study was to determine the prognostic implications of a basaloid carcinoma of the lung. METHODS: This study included a series of 291 surgically resected lung tumors, which were originally diagnosed as a poorly or undifferentiated carcinoma, a small cell carcinoma, or an atypical carcinoid. Of these, 35 basaloid carcinoma patients were identified and compared with 167 poorly differentiated squamous cell carcinoma (PDSC) patients in terms of the preoperative clinical data, the procedure performed, and the survival outcome. RESULTS: The overall incidence of basaloid carcinoma was 4.8%. The actuarial 5-year survival rate was 40.6% in patients with PDSC and 36.5% in those with basaloid carcinoma (p = 0.86). In stage I and II patients, the actuarial 5-year survival rate was 53.9% in the PDSC group and 57.2% in the basaloid group (p = 0.97). There were no differences in the recurrence rate and the relapse pattern (p = 0.584). Cox's proportional hazards model revealed that an age equal to 60 years old (hazard ratio 2.179, p = 0.000) and an advanced stage (hazard ratio 2.264, p = 0.000) were the risk factors for postoperative survival in both groups. CONCLUSIONS: Basaloid carcinoma of the lung does not have a worse prognosis than the other nonsmall cell lung cancers. Although it is obvious that a basaloid carcinoma is a unique histologic entity, it does not require a different treatment modality due to the similar clinical behavior with other nonsmall cell lung cancers.

Basal Cell Carcinoma↗
PubMed2003

Pulmonary epithelioid hemangioendothelioma with prominent signet ring cell features mimicking metastatic adenocarcinoma.

We report the case of a 65-year-old woman who presented with persistent dry cough and was initially treated for pneumonia without much improvement. Computed tomography of the chest showed a 2.5 cm poorly marginated right infrahilar opacity and multiple ill-defined ground glass opacities scattered throughout the lungs. Computed tomography-guided fine needle aspiration of the right infrahilarmass showed malignant epithelioid cells, many of which were strikingly plasmacytoid with a vacuolated cytoplasm suggesting signet ring cells. A diagnosis of adenocarcinoma with signet ring cell features was made and, in view of the clinical history of multiple masses in the lung, metastatic adenocarcinoma from sites such as gastrointestinal or pancreaticobiliary tract was favored. The patient underwent exploratory thoracotomy during which she was found to have multiple, small pulmonary nodules, one of which was sampled for intraoperative examination. Frozen section of the nodule was interpreted as adenocarcinoma with signet ring cell features, probably metastatic in origin. Histopathologic examination of the pulmonary nodules demonstrated fairly well-delineated lesions with an acellular central zone of hyalinized matrix surrounded by a more cellular zone of moderately pleomorphic epithelioid cells, some of which had a peripherally displaced nucleus and vacuolated cytoplasm resembling signet ring cells. The epithelioid cells were positive for vascular markers CD31 and CD34 and, therefore, a diagnosis of epithelioid hemangioendothelioma was confirmed. This case clearly indicates the importance of recognizing the cytomorphologic and histologic spectrum of this entity to avoid misdiagnosing it as either primary or metastatic adenocarcinoma.

Aged↗
PubMed2003

Perivascular epithelioid cell tumor of the uterus: immunohistochemical, ultrastructural and molecular study.

A case of perivascular epithelioid cell tumor of the uterus is reported, occurring in a 32-year-old woman. The tumor (8.0 cm in dimension) showed exophytic growth from the outer half of the myometrium. Histopathologically, the tumor was composed of thick blood vessels and perivascular epithelioid cells. The neoplastic cells were strongly immunoreactive for HMB45 antigen, CD117 (c-kit), vimentin and the progesterone receptor, but completely negative for S-100 protein, smooth muscle actin, desmin, CD34, the estrogen receptor and p16. The Ki-67 labeling index was low (1.25%). Ultrastructurally, the neoplastic cells had numerous premelanosomes with some glycogen deposits. Single-stranded DNA conformational polymorphism of p53 and methylation-specific polymerase chain reaction of p16 revealed negative results. Definite melanosomes on electron microscopic analysis and coexpression of HMB45 antigen and stem cell factor receptor (CD117) may provide the clue to understanding perivascular epithelioid cell tumor because angiomyolipoma also coexpresses HMB45 antigen and CD117.

Adult↗
PubMed2003

Thymic carcinoma with rhabdoid features.

A case of thymic carcinoma with rhabdoid differentiation is presented. A 67-year-old man who presented with chest pain and hemoptysis was referred to The University of Texas M. D. Anderson Cancer Center (Houston, TX). Radiologic studies revealed a large anterior mediastinal mass. After the initial biopsy and preoperative chemotherapy, a radical thymectomy revealed a stage III thymic carcinoma with a rhabdoid component. The rhabdoid component was characterized by large cells with an eccentric nucleus, prominent nucleolus, and typical paranuclear cytoplasmic inclusions. Immunohistochemical and electron microscopic studies confirmed the presence of rhabdoid cells with the paranuclear cytoplasmic inclusions staining for both pancytokeratin and vimentin. The patient was given postoperative chemotherapy and radiation. He has since developed metastases to the pelvis and is alive with disease at 20 months of follow-up. To our knowledge, this is the first reported case of thymic carcinoma with rhabdoid features.

Aged↗
PubMed2003

Expression of DNA methyltransferases in multistep hepatocarcinogenesis.

Hypermethylation of cell cycle regulators and increased DNA methyltransferase 1 (Dnmt1) mRNA level have been reported in hepatocarcinogenesis. However, the expression of Dnmts has not yet been examined in hepatocellular carcinomas (HCCs). We examined 13 cases of HCCs in dysplastic nodules (DNs) and 28 cases of advanced HCCs for Dnmt1 and Dnmt3a, and compared the results with those of 9 cases of low-grade DNs, 24 cases of high-grade DNs, and 59 cases of nonneoplastic liver tissues from 59 cases of surgically resected livers by immunohistochemical staining. Nuclear expression of Dnmt1 was increased significantly in all HCCs in DNs and advanced HCCs compared with those of nonneoplastic livers, low-grade DNs, and high-grade DNs (P <0.05). Nuclear expression of Dnmt3a was not detectable in nonneoplastic liver and low-grade DN, whereas it was observed in high-grade DNs (7 of 24, 29.2%), HCCs in DNs (7 of 13, 53.8%), and advanced HCCs (11 of 28, 39.3%). Different from Dnmt1 immunostaining, cytoplasmic immunoreactivity for Dmnt3a was significantly decreased or absent in 13 of 24 cases of high-grade DNs (54.1%), 12 of 13 cases of HCCs in DNs (92.3%), and 22 of 28 cases of advanced HCCs (78.6%), compared with nonneoplastic livers and low-grade DNs (P <0.05). Our data suggest that Dnmt1 and Dnmt3a play a role in the early stage of hepatocarcinogenesis and that dysregulation of Dnmt3a may be involved in the progression of HCC. Furthermore, the significantly decreased cytoplasmic immunoreactivity for Dnmt3a in high-grade DNs and HCCs can be used as a diagnostic adjunct.

Carcinoma, Hepatocellular↗
PubMed2003

Intramucosal Helicobacter pylori in the human and murine stomach: its relationship to the inflammatory reaction in human Helicobacter pylori gastritis.

Intramucosal Helicobacter pylori (H. pylori) has been described in biopsy tissues and culture systems. However, the association of intramucosal H. pylori with histopathologic features has not been evaluated. The purpose of this study is to investigate the relationship between intramucosal H. pylori and inflammatory reactions in H. pylori infection. In 113 randomly selected human gastric biopsies and 20 murine stomachs, which were inoculated with SSI every day for a week, immunohistochemical analysis for intramucosal H. pylori was done and correlated with histologic parameters. Electron microscopic examination was done on murine stomachs. H. pylori infection was present in 104 gastric biopsies and 17 murine stomachs. Intraepithelial immunopositivity for H. pylori was detected in 27 of 104 (26%) biopsies and in 11 of 17 (65%) murine stomachs. Lamina proprial immunopositivity for H. pylori was present in 51 of 104 (48%) biopsies. Neutrophil-associated immunopositivity for H. pylori was observed in 22 of 90 (24%) biopsies with H. pylori chronic active gastritis. Lamina proprial and neutrophil-associated immunopositivity for H. pylori correlated significantly with the density of H. pylori and the grade of acute inflammatory reaction in H. pylori gastritis. Intramucosal location of H. pylori itself or its antigen is closely associated with acute inflammatory reactions and may play an important role in establishing a persistent infection in chronic H. pylori gastritis. Furthermore, lamina proprial and/or neutrophil-associated H. pylori appears to be more important than intraepithelial H. pylori in acute inflammatory reactions of H. pylori gastritis.

Animals↗
PubMed2003

Localized amyloidosis of seminal vesicle and vas deferens: report of two cases.

We reported localized amyloidosis involving seminal vesicles and vasa deferentia, which was found in two patients with prostatic adenocarcinoma. A 60-yr-old (Case 1) and a 59-yr-old (Case 2) man came to our hospital with elevation of serum prostate-specific antigen (PSA) and biopsy proven carcinoma, respectively. MRI revealed multiple irregular foci of low signal intensity in the prostates as well as in both seminal vesicles and vasa deferentia on T2-weighted imaging, suggesting prostatic carcinoma with extension to both seminal vesicles and vasa deferentia in both cases. Under the clinical diagnosis of stage III prostatic adenocarcinoma, a radical prostatectomy was performed in both patients. Microscopically, Gleason score 7 adenocarcinoma was observed in both patients. In addition, isolated amyloidosis of both seminal vesicles and vasa deferentia was found without carcinoma involvement. Localized amyloidosis in the seminal vesicles, which is considered as senile process, has been occasionally reported in the autopsy and in the surgical specimens. Amyloid deposition in the vas deferens has also been reported in the literature, however, the deposition mimicking extension of carcinoma has not been reported. In this report, two cases of isolated amyloidosis of the seminal vesicles and vasa deferentia are described with electron microscopic study and literature review.

Adenocarcinoma↗
PubMed2003

Sarcomatoid carcinoma of the gallbladder with a rhabdoid tumor component.

We report the case of a sarcomatoid carcinoma with a rhabdoid tumor component originating in the gallbladder, along with immunohistochemical and electron microscopic findings. A 61-year-old woman presented with a 5-month history of right upper quadrant pain. Ultrasonography and a computed tomographic scan indicated gallbladder cancer. She underwent a cholecystectomy and a common bile duct resection. A firm mass (4.5 cm in greatest dimension) was present in the neck portion of the gallbladder. The mass was firm, solid, yellowish gray, and granular with areas of necrosis. Microscopically, the tumor was a biphasic sarcomatoid carcinoma and consisted of diffusely arranged pleomorphic cells, focally showing rhabdoid features and neoplastic glands with focal mucin production. Heterologous components such as osteoid, chondroid, and rhabdomyoblastic elements were not identified. By immunohistochemical staining, we demonstrated that the rhabdoid cells coexpressed cytokeratin and vimentin. On electron microscopic examination, the rhabdoid tumor cells showed cytoplasmic whorls of intermediate filaments in the cytoplasm and eccentric nuclei. Two months postoperatively, the follow-up computed tomographic scan showed multiple intrahepatic metastases and omental seedings.

Carcinosarcoma↗
PubMed2003

Induction of p53-regulated genes and tumor regression in lung cancer patients after intratumoral delivery of adenoviral p53 (INGN 201) and radiation therapy.

PURPOSE: We designed a prospective single arm Phase II study to evaluate the feasibility and mechanisms of apoptosis induction after Ad-p53 (INGN 201) gene transfer and radiation therapy in patients with non-small cell lung cancer. EXPERIMENTAL DESIGN: Nineteen patients with nonmetastatic non-small cell lung cancer who were not eligible for chemoradiation or surgery were treated as outpatients with radiation therapy to 60 Gy over 6 weeks in conjunction with three intratumoral injections of Ad-p53 (INGN 201) on days 1, 18, and 32. RESULTS: Seventeen of 19 patients completed all planned radiation and Ad-p53 (INGN 201) gene therapy as outpatients. The most common adverse events were grade 1 or 2 fevers (79%) and chills (53%). Three months after completion of therapy, pathologic biopsies of the primary tumor revealed no viable tumor (12 of 19 patients, 63%), viable tumor (3 of 19 patients, 16%), and not assessed (4 of 19 patients, 21%). Computed tomography and bronchoscopic findings at the primary injected tumor revealed complete response (1 of 19 patients, 5%), partial response (11 of 19 patients, 58%), stable disease (3 of 19 patients, 16%), progressive disease (2 of 19 patients, 11%), and not evaluable (2 of 19 patients, 11%). Quantitative reverse transcription-PCR analysis of the four p53 related genes [p21 (CDKN1A), FAS, BAK, and MDM2] revealed that Bak expression was increased significantly 24 h after Ad-p53 (INGN 201) injection and levels of CDKN1A and MDM2 expression were increased over the course of treatment. CONCLUSIONS: Intratumoral injection of Ad-p53 (INGN 201) in combination with radiation therapy is well tolerated and demonstrates evidence of tumor regression at the primary injected tumor. Serial biopsies of the tumor suggest that BAK gene expression is most closely related to Ad-p53 (INGN 201) gene transfer.

Adenoviridae↗
PubMed2003

Epidermal growth factor receptor, cyclooxygenase-2, and BAX expression in the primary non-small cell lung cancer and brain metastases.

PURPOSE: The purpose is to identify biological markers that predict brain metastasis and treatment outcome in non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Samples were obtained from the primary tumors, lymph nodes, and brain metastases of 29 patients with NSCLC who had undergone resection of both the pulmonary tumors and the brain lesions. Samples from 29 patients matched for age, sex, and histology whose pulmonary tumors were resected served as controls. Samples were stained with H&E as well as immunohistochemical stains for epidermal growth factor receptor (EGFR), cyclooxygenase 2 (COX-2), and BAX. Comparisons were made between patients with and without brain metastasis. Independent investigators determined the percentage of positive cells. RESULTS: There was positive correlation in expression of all three biomarkers between primary lung tumors and lymph node metastases. Significantly higher levels of EGFR were found in lymph node metastases in the control group (P = 0.0147). COX-2 expression in brain lesions correlated with expression in primary tumors (P = 0.023). BAX levels were lower in poorly differentiated tumors in lymph node metastases in the control group (P = 0.01) and in brain metastases (P = 0.045). Low EGFR expression and high COX-2 expression in lymph node metastasis were associated with poorer treatment outcome. CONCLUSIONS: Expression of EGFR, COX-2, and BAX in primary lung tumors did not differ between patients with brain metastases from NSCLC and those without brain metastases. These three biomarkers cannot be used to predict brain metastasis. Studies of other biomarkers are under way in an effort to predict brain metastasis among patients with NSCLC.

Adult↗
PubMed2002

Bilateral testicular germ cell tumors: twenty-year experience at M. D. Anderson Cancer Center.

BACKGROUND: The incidence of testicular carcinoma in the United States has increased significantly over the last two decades. Germ cell tumors form the majority of malignant testicular tumors. With advances in diagnosis and therapeutic approaches, germ cell tumors are now highly sensitive to treatment, providing long-term survival. It has been speculated that the incidence of bilateral germ cell tumors may increase due to the improved survival of patients with unilateral germ cell tumors. In this report, the authors present a study of bilateral germ cell tumors of the testis in men who were treated at The University of Texas M. D. Anderson Cancer Center over a 20-year period with emphasis on their incidence, histologic features, and clinical features. METHODS: Between 1978 and 1999, 2431 patients with testicular germ cell tumors were treated at The University of Texas M. D. Anderson Cancer Center. Among these, 24 patients with bilateral germ cell tumors were identified. Clinical records and all available pathology slides of the tumors were reviewed. RESULTS: The overall incidence of bilateral germ cell tumors in the patients with testicular germ cell tumors was 1% (24 of 2431 patients). The incidence was 1.8% (14 of 776 patients) in patients with seminoma and 0.6% (10 of 1655 patients) in patients with nonseminomatous germ cell tumors. Patients with seminoma who were age </= 30 years at the time of initial diagnosis had a higher incidence of bilateral tumors compared with older men. Twenty of 24 patients with bilateral germ cell tumors had metachronous tumors, and 4 patients had synchronous tumors. Among the patients with metachronous tumors, 70% of second tumors occurred within 5 years; the longest interval between the first and second tumors was 15 years. The outcome of patients with bilateral germ cell tumors was excellent; only 1 of 24 patients died of metastatic disease. CONCLUSIONS: The overall incidence of bilateral testicular germ cell tumors was 1% in patients who were treated at The University of Texas M. D. Anderson Cancer Center over the past two decades. The incidence of bilateral germ cell tumors was related to the histologic type of the initial tumor and to the patient's age at initial presentation in patients with seminoma. Thus, patients in the second or third decade of life who presented with seminomas as their initial tumor were more likely to develop a second germ cell tumor compared with patients in the fourth or fifth decade of life. These findings have potentially important implications for clinical management by identifying a population of patients with germ cell tumors who are at risk of developing a second tumor and also for studying risk factors of bilateral germ cell tumors of the testis.

Adolescent↗
PubMed2002

Association of Ki-67, p53, and bcl-2 expression of the primary non-small-cell lung cancer lesion with brain metastatic lesion.

PURPOSE: The study was conducted to determine whether immunohistochemical analysis of Ki-67, p53, and bcl-2 in patients with non-small-cell lung cancer is associated with a higher rate of brain metastases and whether the intrapatient expression of these biomarkers (in the primary tumors vs. brain lesions) is similar. METHODS AND MATERIALS: At the M. D. Anderson Cancer Center, tumors from 29 case patients with primary lung tumor and brain metastasis and 29 control patients with primary lung tumor but no brain metastasis were resected and examined for immunohistochemical expression. Ki-67, p53, and bcl-2 were analyzed in resected primary lung, lymph node, and metastatic brain tumors. Each control patient was matched by age, gender, and histology to a patient with brain metastasis. RESULTS: No significant differences in patient survival characteristics were detected between the case group and control group. Also, difference in patient outcome between the two groups was not generally predicted by biomarker analysis. However, when the groups were combined, the biomarker analysis was predictive for certain patient outcome end points. Using median values as cutoff points between low and high expression of biomarkers, it was observed that high expression of Ki-67 (>40%) in lung primaries was associated with poorer disease-free survival (p = 0.04), whereas low expression of p53 in lung primaries was associated with poorer overall survival (p = 0.04), and these patients had a higher rate of nonbrain distant metastases (p = 0.02). The patients with brain metastases were particularly prone to developing nonbrain distant metastases if the percentage of p53-positive cells in brain metastases was low (p = 0.01). There was a positive correlation in the expression of Ki-67 (p = 0.02)(r(2) = 0.1608), as well as p53 (p < 0.001) (r(2) = 0.7380), between lung primaries and brain metastases. Compared to Ki-67 and p53, bcl-2 was the least predictive. CONCLUSION: Differences in biomarker expression between the case and control groups did not serve as significant predictors of brain metastasis or patient survival. There was a strong correlation between lung primary biomarker expression and brain metastasis expression for Ki-67 and p53. Univariate analysis showed that low p53 and high Ki-67 expression predicted poor prognosis. This study shows that there may be a strong correlation between biomarker expression in non-small-cell lung cancer primary tumors and their brain metastases.

Adult↗
PubMed2002

Heterogeneous expression of Ku70 in human tissues is associated with morphological and functional alterations of the nucleus.

Ku70 is a subunit of DNA-protein kinase complex and involved in diverse intranuclear events including the repair of double-stranded DNA breaks. Ku70 is rich in the interphase nucleus of cultured cells. In human tissues, however, the distribution of Ku70 has not yet been systematically examined. To characterize the difference of Ku70 distribution between cells of human tissues and cultured cells, the expression of Ku70 was examined in various normal and neoplastic human tissues by immunohistochemistry and immunoblot. In addition, the role of Ku70 in the cellular response against ionizing radiation (IR) was analysed in fibroblasts after exposure to 5 Gy IR and apoptotic indices were examined in Ku70-overexpressed fibroblasts from an ataxia telangiectasia patient and in normal fibroblasts, before and after irradiation. In contrast to cultured cells, Ku70 was not detected in some interphase cells of human tissues and was distributed heterogeneously, even in the same nucleus. Ku70 expression was strikingly low in terminally differentiated cells such as neutrophils, eosinophils, glomerular capillary endothelial cells and fibroblasts, and was absent in spermatids. In spermatocytes, Ku70 was tightly integrated with chromosome filaments, unlike other somatic cells under mitosis. After exposure to IR, Ku70 expression was not increased in ataxia telangiectasia fibroblasts, but was significantly increased in normal fibroblasts. Most of the increased Ku70 was of soluble nuclear protein fraction. Furthermore, overexpression of Ku70 increased radiation resistance both in ataxia telangiectasia fibroblasts and normal fibroblasts. The presented data indicate that the distribution of Ku70 in cells of human tissues is closely associated with the cell cycle, cellular differentiation, nuclear shape and the process of repair of DNA damage caused by IR.

Adult↗
PubMed2002

Epstein-barr virus-positive gastric carcinoma demonstrates frequent aberrant methylation of multiple genes and constitutes CpG island methylator phenotype-positive gastric carcinoma.

CpG island methylation is an important mechanism for inactivating the genes involved in tumorigenesis. Gastric carcinoma (GC) is one of the tumors that exhibits a high frequency of aberrant CpG island methylation. There have been many reports suggesting a close link between Epstein-Barr virus (EBV) and the development of GC. However, little is known about the oncogenic mechanism of EBV in gastric carcinogenesis. Twenty-one cases of EBV-positive GC and 56 cases of EBV-negative GC were examined for aberrant DNA methylation of the CpG islands of 19 genes or loci and the differences in the methylation frequency between EBV-positive and -negative GCs were investigated to determine a role of aberrant methylation in EBV-related gastric carcinogenesis. The average number of methylated genes or loci was higher in EBV-positive GCs than in EBV-negative GCs (13.4 versus 7.8, respectively, P < 0.001). EBV-positive GCs showed methylation in at least 10 CpG islands (52.6% of the tested genes), whereas 62.5% of EBV-negative GCs showed methylation in <10 CpG islands. THBS1, APC, p16, 14-3-3 sigma, MINT1, and MINT25 were methylated at a frequency >90% in EBV-positive GCs. The methylation frequency difference in the respective CpG islands between EBV-positive and -negative GCs was statistically significant (P < 0.05). Among these genes or loci, the methylation frequency of p16 in the EBV-positive GCs was more than three times higher than in the EBV-negative GCs. The PTEN, RASSF1A, GSTP1, MGMT, and MINT2 were methylated in EBV-positive GCs at a frequency of more than three times that of the EBV-negative GCs. These results demonstrate a relationship between EBV and aberrant methylation in GC and suggest that aberrant methylation may be an important mechanism of EBV-related gastric carcinogenesis.

CpG Islands↗