• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.2
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• pp.164-173
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• 2000

The p16 protein is a cyclin dependent kinase inhibitor that inhibits cell cycle progression from $G_1$ phase to S phase in cell cycle. Many p16 gene mutations have been noted in many cancer-cell lines and in some primary cancers, and alterations of p16 gene function by DNA methylation have been noticed in various kinds of cancer tissues and cell-lines. There have been a large body of literature has accumulated indicating that abnormal patterns of DNA methylation (both hypomethylation and hypermethylation) occur in a wide variety of human neoplasma and that these aberrations of DNA methylation may play an important epigenetic role in the development and progression of neoplasia. DNA methylation is a part of the inheritable epigenetic system that influences expression or silencing of genes necessary for normal differentiation and proliferation. Gene activity may be silenced by methylation of up steream regulatory regions. Reactivation is associated with demethylation. Although evidence or a high incidence of p16 alterations in a variety of cell lines and primary tumors has been reported, that has been contested by other investigators. The precise mechanisms by which abnormal methylation might contribute to carcinogenesis are still not fully elucidated, but conceivably could involve the modulation of oncogene and other important regulatory gene expression, in addition to creating areas of genetic instability, thus predisposing to mutational events causing neoplasia. There have been many variable results of studies of head and neck squamous cell carcinoma(HNSCC). This investigation was studied on 13 primary HNSCC for p16 gene status by protein expression in immunohistochemistry, and DNA genetic/epigenetic analyzed to determine the incidence, the mechanisms, and the potential biological significance of its Inactivation. As methylation detection method of p16 gene, the methylation specific PCR(MSP) is sensitive and specific for methylation of any block of CpG sites in a CpG islands using bisulfite-modified DNA. The genomic DNA is modified by treatment with sodium bisulfate, which converts all unmethylated cytosines to uracil(thymidine). The primers designed for MSP were chosen for regions containing frequent cytosines (to distinguish unmodified from modified DNA), and CpG pairs near the 5' end of the primers (to provide maximal discrimination in the PCR between methylated and unmethylated DNA). The two strands of DNA are no longer complementary after bisulfite treatment, primers can be designed for either modified strand. In this study, 13 paraffin embedded block tissues were used, so the fragment of DNA to be amplified was intentionally small, to allow the assessment of methylation pattern in a limited region and to facilitate the application of this technique to samlples. In this 13 primary HNSCC tissues, there was no methylation of p16 promoter gene (detected by MSP and automatic sequencing). The p16 protein-specific immunohistochemical staining was performed on 13 paraffin embedded primary HNSCC tissue samples. Twelve cases among the 13 showed altered expression of p16 proteins (negative expression). In this study, The author suggested that low expression of p16 protein may play an important role in human HNSCC, and this study suggested that many kinds of genetic mechanisms including DNA methylation may play the role in carcinogenesis.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.3
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• pp.218-228
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• 2010

Components of dental resin-based restorative materials are reported to leach from the filling materials even after polymerization. Hydroquinone (HQ) is one of the major monomers used in the dental resin and is known as a carcinogen. Thus, carcinogenic risk of HQ leaching from the dental resin becomes a public health concern. The present study attempted to examine the carcinogenic potentials of HQ on the human epithelial cell, which is the target cell origin of the most of oral cancers. Cytotoxicity of HQ was observed above 50${\mu}M$ as measured by LDH assay, indicating a relatively low toxicity of this substance in human epithelial cells. The parameters of neoplastic cellular transformation such as cell saturation density, soft agar colony formation and cell aggregation were analyzed to examine the carcinogenic potential of HQ. The study showed that 2-week exposure of HQ showed the tendency of increase in the saturation density and the significant enhancement of soft agar colony formation at the highest dose, 50 ${\mu}M$ only. It is suggested that HQ has a weak potential of carcinogenicity. When cells were treated with HQ and TPA, a well-known tumor promoter, the parameters of neoplastic cellular transformation was significantly increased. This result indicates that the potential risk of carcinogenicity from HQ is largely dependent upon the presence of promoter. Exposure of 50 ${\mu}M$ HQ increased the time-dependent apoptosis as measured by the ELISA kit. This concentration coincides with a dose of neoplastic transformation, indicating a possible link between apoptosis and HQ-induced cellular transformation. Hydroquinone generated Reactive Oxygen Species (ROS) which was evidenced by the treatment of antioxidants such as trolox and N-acetyl cysteine and the GSH depleting agent, BSO. Antioxidants blocked the generation of ROS and the GSH depleting agent, BSO dramatically increased the ROS production. Since HQ is known to increase ROS production thru activation of transcriptional factor such as c-Myb and Pim-1, it is speculated that ROS generation by HQ plays a role in the activation of oncogene, which may lead to neoplastic transformation. In addition, ROS is involved in the alteration of signal transduction, which regulates the apoptosis in many cellular systems. Thus, ROS-mediated apoptosis may be involved in the HQ-induced carcinogenic processes. Protein kinase C (PKC) is known to play pivotal roles in neoplastic transformation of cells and its high expression is often found in a variety of types of tumors including oral cancer. PKC translocation of PKC-${\alpha}$ was observed following HQ exposure. Altered signaling system may also play a role in the transformation process. Taken together, HQ leached from the dental resin does not pose a significant threat as a cancer causing agent, but its carcinogenic potential can be significantly elevated in the presence of promoter. The mechanism of HQ-induced carcinogenesis involved ROS generation, apoptosis and altered signaling pathway. The present study will provide a valuable data to estimate the potential risk of HQ as a carcinogen and understand mechanism of HQ-induced carcinogenesis in human epithelial cells.

• Journal of Gastric Cancer
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• v.6 no.2
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• pp.76-83
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• 2006

Purpose: Endoscopic incision and submucosal dissection (EISD) is a technique that is being implemented for the resection of gastric adenomas and early gastric cancer (EGC). Since EISD requires a high degree of skill and experience, and due to its association with a moderate risk of gastrointestinal bleeding, its use has been limited. The objective of this study is to investigate the clinical benefits of EISD based upon clinical data on the EISD procedure. Materials and Methods: This study was conducted at Soonchunhyang University Hospital and it included 179 gastric adenoma and early gastric carcinoma lesions from 164 patients who had undergone an EISD from February 2003 to May 2005. Results: Among the total of 179 lesions, the distributions of EGC and adenomas were 70.3% (126/179) and 23.4% (42/179) respectively. The sizes of lesions were divided into 10 mm or less, $11{\sim}20\;mm,\;21{\sim}30\;mm$ and greater than 31 mm and each rates are 10.0% (18/179), 46.3% (83/179), 30% (50/179) and 15.0% (28/179). Among 120 cases which could be measured depth of lesion in according to pathologic findings, m1 (0.8%, 1/120), m2 (38.3%, 46/120), m3 (25%, 57/120), sm1 (11.7%, 14/120), sm2 (1.6%, 2/120) were diagnosed as early stages of gastric cancer. The complete resection rate was 85.2% (150/176) and en-bloc resection rate was 96.0% (169/176). Complications as such as perforation and bleeding developed in 4.4%(8/179) and 21.2% (38/179), respectively. Conclusion: EISD is an effective in the endoscopic treatment for gastric adenoma and early gastric cancers. However, further evaluation of this method and long-term follow-up will be necessary for an evaluation of the recurrence rate after resection of a tumor.

• Journal of Gastric Cancer
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• v.6 no.2
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• pp.97-102
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• 2006

Purpose: The prognosis for patients with a Borrmann type IV gastric cancer is extremely poor despite an aggressive surgical approach. We evaluated the clinicopathological features for Borrmann type IV cancers to find treatment strategy. Materials and Methods: The 1098 patients with advanced gastric cancer who underwent surgical resection between 1990 and 2001 were analyzed. These patients were divided into two groups: 81 patients with a Borrmann type IV carcinoma, and 1017 patients with all other types of gastric carcinomas. Results: Patients with a Borrmann type IV carcinoma were younger than those with other types, and female was prevalent (p=0.000). Of the patients with a Borrmann type IV gastric carcinoma, 68 patients (84%) were classified as stage III or IV at the initial diagnosis. The histologic type was commonly undifferentiated and serosal infiltration; nodal involvement and lymphatic invasion were more frequent in patients with a Borrmann type IV than in those with other types of cancer. Multivariate analysis confirmed that the extent of lymph node metastasis was a negative prognostic factor for Borrmann type IV gastric carcinomas. The curability for a Borrmann type IV carcinoma was only 53.1%, and peritoneal dissemination rate was 25.9%. The predominant pattern of recurrence for a Borrmann type IV gastric carcinoma was peritoneal dissemination, and it was significantly different with other types (93.1% vs 55.8%, P<0.05). The 5-year survival rate of patients with a Borrmann type IV gastric carcinoma was significantly lower than those of patients with other types of cancer, even though a curative resection had been accomplished (26% vs 63%, p<0.005). The 5-year survival rates of patients with a Borrmann type IV carcinoma following a curative resection were 44.9%, 24%, and 0% for stages II, III and IV, respectively (p<0.05). Conclusion: Because the prognosis for patients of a Borrmann type IV gastric cancer is extremely poor despite a curative resection, preoperative and/or intraperitoneal chemotherapy should be considered. And diagnostic laparoscopy and peritoneal cytology may be used to play an important role in accurate staging workup. (J Korean Gastric Cancer Assoc 2006;6:97-102)

• Journal of Gastric Cancer
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• v.7 no.4
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• pp.185-192
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• 2007

Purpose: RUNX3, a novel tumor suppressor, is frequently inactivated in gastric cancer. In the present study, we examined the pattern of RUNX3 expression in gastric cancer cells from gastric cancer specimens and the impact of its alteration on clinical outcome. Materials and Methods: A total of 124 samples of both gastric cancer and normal tissue were obtained from 124 patients who underwent curative gastrectomy at the Seoul Medical Center from January 2001 to December 2005. RUNX3 expression was determined by immunohistochemical staining, and the results were analyzed. Statistical analysis wabased on clinicopathological findings and differences in survival rates. Results: The mean age of the patients was 61 years, and the male:female ratio was 1.9:1. The expression rate of RUNX3 was 59.7% (74/124). The expression rate was higher in differentiated gastric cancers (nucleus: 9.1%, cytoplasm: 57.6%) than in the undifferentiated types (nucleus: 5.2%, cytoplasm: 46.6%) (P=0.133). The 5-year survival rates according to RUNX3 expression determined from cancer tissue were 88.9% for the nucleus $\pm$ cytoplasm(+) group of patients, 76.1% for the cytoplasm only (+) group of patients, and 65.3% for the RUNX3 negative expression group of patients (P=0.626). Only UICC TNM staging showed statistical significance related to the survival rate, as determined by multivariate analysis. Conclusion: The RUNX3 expression rate was higher in differentiated gastric cancer than in the undifferentiated types without significance. Although RUNX3 expression predicted better survival, based on multivariate analysis, the finding was not statistically significant. More cases should be further evaluated.

• Tuberculosis and Respiratory Diseases
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• v.49 no.1
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• pp.49-59
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• 2000

Backgrounds : Recent cytogenetic studies indicated that long of the long arm of chromosome 5 is a frequent event in small cell lung canær (SCLC), suggesting the presence of a tumor suppressor gene in its place. To map the precise tumor-suppressor loci on the chromosome arm for further positional cloning efforts, we tested 15 primary SCLCs. Methods : The DNAs extracted from paraffin-embedded tissue blocks with primary tumor and corresponding control tissue were investigated. Nineteen polymorphic microsatellite markers located in the long arm of chromosome 5 were used in the microsatellite analysis. Results : We found that ten (66.7%) of 15 tumors exhibited LOH in at least one of tested microsatellite markers. Two (13%) of 10 tumors exhibiting LOH lost a larger area in chromosome 5q. LOH was observed in five common deleted regions at 5q. Among those areas, LOH between 5q34-qter and 5q35.2-35.3 was most frequent (75%). LOH was also observed in more than 50% of the tumors at four other regions, between 5q14-15 and 5q23-31, 5q31.1, 5q31.3-33.3, and 5q34-35. Three of 15 tumors exhibited shifted bands in at least one of the tested microsatellite markers. Shifted bands occurred in 2.5% (7 of 285) of the loci tested. Conclusion : Our data demonstrated that at least five tumor-suppressor loci exist in the long arm of chromosome 5 and that they may play an important role in small cell lung cancer tumorigenesis.

• Tuberculosis and Respiratory Diseases
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• v.51 no.2
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• pp.108-121
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• 2001

Background : The $p16^{INK4a}$ (p16) twnor suppressor gene is frequently inactivated in hwnan non-small cell lung cancers (NSCLCs), predominantly through homozygous deletion or in association with aberrant promotor hypermethylation. Death-associated protein kinase (DAPK) gene influences interferon $\gamma$-induced apoptotic cell death and has important role in metastasis of lung cancer in animal model. Hypermethylation of promoter region of DAP kinase gene may suppress the expression of this gene. Methods : This study was performed to investigate the aberrant methylation of p16 or DAP kinase in 35 resected primary NSCLCs by methylation-specific PCR (MSP), and demonstrated frequency, diagnostic value and clinical implication of aberrant methylation of two genes. Results : Thirty-two cases were male patients, and 3 cases were female patients with an average age was 57. $8{\pm}10.5$ years. The histologic types of lung cancer were 22 of squamous cell carcinoma, 12 of adenocarcinoma, 1 of large cell carcinoma. Pathologic stages were 11 cases of stage I (1 IA, 10 IB), 13 cases of stage II (1 IIA, 12 IIB), and 11 cases of stage III (9 IIIA, 2 IIIB). Regarding for the cancer tissue, p16 aberrant methylation was noted in 13 case of 33 cases (39.4%), DAP kinase in 21 cases of 35 cases (60%). Age over 55 year was associated with p16 aberrant methylation significantly (p<0.05). Methylation status of two genes was not different by smoking history, histologic type, size of tumor, lymph node metastasis and disease progression of lung cancer. There was no correlation between p16 and DAP kinase hypermethylation. Conclusion: This investigation demonstrates that aberrant methylation of p16 tumor suppressor gene or DAP kinase showed relatively high frequency (74.3%) in NSCLCs, and that these genes could be a biologic marker for early detection of lung cancer.

• Tuberculosis and Respiratory Diseases
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• v.57 no.3
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• pp.265-272
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• 2004

Background : RASSF1A, which is one of tumor suppressor genes, is frequently inactivated by hypermethylation of the promoter region in a variety of human cancers, including lung cancer. This study was performed to investigate the association between RASSF1A methylation and the clinicopathological factors in patients with squamous cell carcinoma of the lung. Methods : Eighty-one samples from the patients with squamous cell carcinoma of lung were examined. The promoter methyation of RASSF1A was analyzed by methylation specific PCR and sequencing. Statistical analysis was made to examine the association between RASSF1A methylation and the clinicopathological parameters. Results : RASSF1A methylation was observed in 37.0 % (30 of 81) of the patients with squamous cell carcinoma of the lung. RASSF1A methylation was found to be associated with cellular differentiation(p=0.0097) and the overall survival(p=0.0635). However, there was no association between RASSF1A methylation and the other clinicopathological parameters, such as the pathological TNM stage, the recurrence rate, lymph node invasion and the amount of cigarettes smoked. Conclusion : RASSF1A methylation might be associated with a poor prognosis in patients with squamous carcinoma of the lung. A larger scale study is needed.

• Tuberculosis and Respiratory Diseases
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• v.62 no.4
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• pp.284-289
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• 2007

Background: To define the clinical features of patients with lung and upper aerodigestive tract cancer through a review of the histopathology, clinical features and follow-up results. Methods: Patients with lung and upper aerodigestive tract cancer who were diagnosed in Young dong Severance Hospital from 1992 to 2005, were retrospectively reviewed. The clinical data, radiologic findings, pathologic findings, treatment modalities were evaluated. Result: There was a total of 20 patients with aerodigestive tract cancer who were diagnosed with lung cancer over a 13 years period. The mean age was $58.45{\pm}15.09$ years and 19 cases were male. There were 14 smokers with an average pack year of 46 years. Twelve patients had aerodigestive tract cancer and later developed lung cancer, and 5 lung cancer patients were later diagnosed with aerodigestive tract cancer. Conclusion: These results suggest that cancers of the aerodigestive tract and lung can arise as either dependent or independent events and most aerodigestive tract cancer patients who developed lung cancer are not treated properly. Therefore, regular low dose chest CT with close suspicion is needed to properly manage upper aerodigestive tract cancer patients.

• Progress in Medical Physics
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• v.15 no.1
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• pp.30-38
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• 2004

Purpose: To develop a whole body frame for the purpose of reducing patient motion and minimizing setup error for extra-cranial stereotactic radiotherapy, and to evaluate the repositioning setup error of a patient in the frame. Materials and Methods: The developed whole body frame is composed of a base plate, immobilizer, vacuum cushion, ruler and belts. The dimension of the base plate is 130 cm in length, 50 cm in width and 1 cm in thickness. The material used in the base plate of the frame was bakelite and the immobilizer was made of acetal. In addition, Radiopaque angio-catheter wires were engraved on the base plate for a coordinate system to determine the target localization. The measurement for radiation transmission and target localization is peformed in order to test the utilization of the frame. Also, a Matlab program analyzed the patients setup error by using the patient's setup images obtained from a CCTV camera and digital record recorder (DVR). Results: A frame that is useful for CT simulation and radiation treatment was fabricated. The frame structure was designed to minimize collisions from the changes in the rotation angle of the gantry and to maximize the transmission rate of the Incident radiation at the lateral or posterior oblique direction. The lightening belts may be used for the further reduction of the patient motion, and the belts can be adjusted so that they are not in the way of beam direction. The radiation transmission rates of this frame were measured as 95% and 96% at 10 and 21 MV, respectively. The position of a test target on the skin of a volunteer is accurately determined by CT simulation using the coordinate system in the frame. The estimated setup errors by Matlab program are shown 3.69$\pm$1.60, 2.14$\pm$0.78 mm at the lateral and central chest, and 7.11 $\pm$2.10, 6.54$\pm$2.22 mm at lateral and central abdomen, respectively. The setup error due to the lateral motion of breast is shown as 6.33$\pm$ 1.55 mm. Conclusion: The development and test of a whole body frame has proven very useful and practical in the radiosurgery for extra-cranial cancers. It may be used in determining target localization, and it can be used as a patient immobilization tool. More experimental data should be obtained in order to improve and confirm the results of the patient setup error.