• Molecules and Cells
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• v.38 no.6
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• pp.548-561
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• 2015

By combining conventional single cell analysis with flow cytometry and public database searches with bioinformatics tools, we extended the expression profiling of thymic stromal cotransporter (TSCOT), Slc46A2/Ly110, that was shown to be expressed in bipotent precursor and cortical thymic epithelial cells. Genome scale analysis verified TSCOT expression in thymic tissue- and cell type- specific fashion and is also expressed in some other epithelial tissues including skin and lung. Coexpression profiling with genes, Foxn1 and Hoxa3, revealed the role of TSCOT during the organogenesis. TSCOT expression was detected in all thymic epithelial cells (TECs), but not in the $CD31^+$endothelial cell lineage in fetal thymus. In addition, ABC transporter-dependent side population and Sca-$1^+$ fetal TEC populations both contain TSCOT-expressing cells, indicating TEC stem cells express TSCOT. TSCOT expression was identified as early as in differentiating embryonic stem cells. TSCOT expression is not under the control of Foxn1 since TSCOT is present in the thymic rudiment of nude mice. By searching variations in the expression levels, TSCOT is positively associated with Grhl3 and Irf6. Cytokines such as IL1b, IL22 and IL24 are the potential regulators of the TSCOT expression. Surprisingly, we found TSCOT expression in the lung is diminished in lung cancers, suggesting TSCOT may be involved in the suppression of lung tumor development. Based on these results, a model for TEC differentiation from the stem cells was proposed in context of multiple epithelial organ formation.

• Journal of Yeungnam Medical Science
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• v.27 no.2
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• pp.98-104
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• 2010

Primary anterior mediastinal neoplasms comprise a diverse group of tumors and account for 50% of all mediastinal masses. Thymic epithelial neoplasm are most common and classified into thymoma, invasive thymoma, and thymic carcinoma. Neuroendocrine differentiation of thymic epithelial neoplasm are rare malignancies. Germ cell tumor (GCT) is second most common anterior mediastinal tumor and most of them are mature cystic teratoma. Malignant mediastinal GCT are rare than benign. Primary thoracic lymphoma is rare than thoracic involvement of systemic lymphoma and most common location of primary thoracic lymphoma is anterior mediastinum. The clinical and radiologic appearance of the most common masses are reviewed.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5581-5585
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• 2012

Objective: To explore the relationship between computed tomography (CT) manifestations of thymoma and its WHO pathological classification. Methods: One hundred and five histopathologically confirmed cases were collected for their pathological and CT characteristics and results were statistically compared between different pathological types of thymoma. Results: Tumor size, shape, necrosis or cystic change, capsule integrity, invasion to the adjacent tissue, lymphadenopathy, and the presence of pleural effusion were significantly different between different pathological types of thymomas (P<0.05). Type B2, B3 tumors and thymic carcinomas were greater in size than other types. More than 50% of type B3 tumors and thymic carcinomas had a tumor size greater than 10 cm. The shape of types A, AB, and B1 tumors were mostly round or oval, whereas 75% of type B3 tumors and 85% of thymic carcinomas were irregular in shape. Necrosis or cystic change occurred in 67% of type B3 thymomas and 57% of thymic carcinomas, respectively. The respective figures for capsule destruction were 83% and 100%. Increases in the degree of malignancy were associated with increases in the incidence of surrounding tissue invasion: 33%, 75%, and 81% in type B2, type B3, and thymic carcinomas, respectively. Pleural effusion occurred in 48% of thymic carcinomas, while calcification was observed mostly in type B thymomas. Conclusions: Different pathological types of thymic epithelial tumors have different CT manifestations. Distinctive CT features of thymomas may reflect their pathological types.

• Journal of Chest Surgery
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• v.27 no.6
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• pp.497-501
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• 1994

We have experienced a case of primary thymic carcinoma. A 39 year old female patient admitted with incidentally detected mediastinal mass on chest film.The tumor showed invasion to surrounding tissues and the mediastinal lymphadenopathies were also noted. Invasion to contiguous mediastinal structures made complete surgical extirplation impossible and the biposy findings revealed primary thymic carcinoma. Primary thymic carcinoma is a rare neoplasm originating from the thymic epithelial cells. Clinical behavior of the thymic carcinoma is much different from it`s benign counterpart and several pathologic variants were reported.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2745-2748
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• 2012

Aims: To study KIT (CD117) expression in thymic epithelial tumors in China, and investigate diagnostic and clinical significance. Material and Methods: Thymic epithelial tumors (TETs) from 102 patients (3 type A, 29 type AB, 5 type B1, 22 type B2, 29 typeB3 and 16 thymic carcinomas) were examined. Immunohistochemical staining with an antic-kit monoclonal antibody was performed on a tissue microarray. Relationships between KIT positive expression and the TET clinical characteristics (WHO histologic classification and Masaoka stage system) were analysed. Results: The KIT positive expression rate was significantly higher in thymic carcinoma (60%, 9/16) than in thymoma (8%, 7/86), a strong correlation being found with the WHO classification, but not the Masaoka tumor stage. The overall survival for patients with KIT positive lesions was significantly worse. Conclusions: KIT is a good molecule marker to differentially diagnose thymic carcinoma from thymoma, while also serving as a predictor of prognosis for TETs. Further research into KIT mutations in Chinese TETs should be conducted to assess the efficacy of targeted therapy.

• Applied Microscopy
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• v.27 no.1
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• pp.31-46
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• 1997

Ultrastructure of mouse thymus was evaluated, following the administration of potassium dichromate and mercuric chloride, the heavy metals of evironmental pollutants. Potassium dichromate (20 mg/kg) or mercuric chloride solutions (10 mg/kg) were subcutanously injected to the mice. Six hours, three days and two weeks after the injections, animals were sacrificed. Thymic tissues were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde solutions. The procedure was followed by the fixation in 1% osmium tetroxide solutions. Washed and dehydrated tissue-blocks were embedded in the araldite mixture. Ultra-thin sections were stained with uranyl acetate-lead citrate solutions. Results observed were as follows: 1. In electron microscopy, cortical population of thymocytes in the thymus of experimental groups were reduced. especially in the outer cortex. Subcapsular cortices of potassium dichromate treated mice were filled with many epithelial reticular cells, whereas the similar area of mercuric chloride-treated mice exhibited large intercellular spaces. 2. In the thymus of mercuric chloride treated group, large intercellular spaces were formed by shrinkage of epithelial reticular cells, and the space was invaded by numerous cytoplasmic projections of macrophages. Thymocytes nuded out from the shrunken cytoplasm of epithelial reticular cells, presented numerous microvilli. 3. In the thymus of potassium dicromate treated group, many activated macrophages and plasma cells migrated into thymic cortices. 4. In the perivascular spaces of thymic cortices of potassium dichromate- and mercuric chloride-treated mice, activated macrophages. plasma cells, collagen fibrils, and flocculent substance of exudated materials were exhibited. From the above findifgs, it was concluded that potassium dichromate or mercuric chloride could disturb the normal differentiation or 'education' of T cells in the thymic cortex. In turn, these heavy metals may hurt the immunological defense mechanism.

• Journal of Chest Surgery
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• v.37 no.8
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• pp.684-690
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• 2004

Background: Primary thymic epithelial neoplasm is a type of mediastinal tumors that have various biologic and morphologic features. In this study, we reclassified 59 cases of thymic epithelial tumors by the new WHO classification. We inquired whether the new WHO classification has independent prognostic relevance by analyzing clinical characteristics of thymic epithelial tumors including Masaoka's clinical stage. Material and Method: From December 1986 to August 2003, 59. patients who underwent surgery in the Keimyung University Dongsan Medical Center with definite diagnosis of thymic epithelial tumor were studied. We analyzed the histologic subtype (WHO classification). clinical stage (Masaoka's clinical stage) and patient's characteristics (sex, age, myasthenia gravis, tumor size, invasion. recurrence, metastasis) as prognostic factors. We analyzed the relationship between histologic subtype and clinical stage. Result: 32 patients were male and 27 were female. Mean age was 50.1$\pm$14.2. From WHO A to C, all thymic epithelial tumors were reclassified by the new WHO classification. Six patients (10.2%) had Type A, 7 (11.9%) had Type AB, 7 (11.9%) had Type B$_1$, 10 (16.9%) had Type B$_2$ and 7 (11.9%) had Type B$_3$, 22 (37.3%) had Type C. Two factors were shown by multivariate analysis to be associated with a favorable prognosis: completeness of resection (p=0.003) and non-invasiveness (p=0.001). The overall 5-year survival of the 59 patients was 53%, subtype A and AB were 92.3%, B$_1$ and B$_2$ were 70.2%, and B$_3$ and C were 26.1%. The association between histologic subtype and invasive behavior (stage) was statistically significant (p<0.001). Conclusion: The WHO classfication is not only a histologic classfication of the thymic epithelial tumors but also a significant prognostic factor that influence the survival of thymic epithelial tumors.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.26 no.2
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• pp.133-136
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• 2015

Spindle epithelial tumor with thymus-like differentiation (SETTLE) is an extremely rare type of thyroid tumor, with spares reports on its clinical course. SETTLE is derived from branchial pouch or thymic remnants, and classified as a low grade, malignant neoplasm due to its indolent growth and tendency to develop delayed metastasis. Therefore, stringent initial workups and long-term follow-up are required to prevent misdiagnosis. We present a case of recurrent spindle epithelial tumor with thymus-like differentiation (SETTLE) in the glottis of 57 year-old male patient, who had a history of surgical excision for the SETTLE from the thyroid gland 5 years ago. Transoral CO2 laser surgery was performed to remove the glottic tumor and there was no evidence of local recurrence at 11 months postoperatively.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.718-722
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• 1999

Thymoma is the most common tumor in the compartment of anterior mediastinum. The malignant thymoma is classified into invasive thymoma(category I) and thymic carcinoma(category II). Recently, well-differentiated thymic carcinoma is a proposed category 1.5 used to describe a subset of thymic epithelial tumors, allowing for the existence of intermediate form based on the clinical features and the histological characteristics. Thymic cyst is a congenital or a acquired disorder. Congenital thymic cyst may develop due to failure of the thymopharyngeal duct to obliterate and acquired thymic cyst develops from inflammation(multilocular thymic cyst), or neoplasm(cystic thymoma). Cystic degeneration in thymoma is a relatively frequent but focal event. In rare cases, the process proceeds to the extent that most or all of the lesion becomes cystic. Until now, well-differentiated thymic carcinoma with extensive cystic degeneration has not been reported in our country. We experienced a case of 14 year-old female patient showing extensive cystic degeneration in well-differentiated thymic carcinoma. And so we report it with review of the articles related.

• Journal of Chest Surgery
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• v.32 no.8
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• pp.726-731
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• 1999

Background: The distinction between non-invasive and invasive or thymic carcinoma has been severely compromised by lack of objective morphological criteria. A reliable biological marker of tumor aggressiveness is, therefore, mandatory for predicting tumor behavior. Material and Method: Thirty thymic epithelial tumors, including 7 non-invasive thymoma, 10 invasive thymoma, and 13 thymic carcinoma of the Rosai's classification; and 5 stage I, 7 stage II, 2 stage III, and 3 stage IVa of the Masaoka stage of thymoma were investigated for expression of bcl-2 and p53 proteins by immunohistochemistry. Result: The thymic epithelial cells showed positive immunostain for bcl-2 in 0 (0%), 3 (30%), 8 (61.5%) of categories in the Rosai's classification respectively and in 0 (0%), 1 (14.3%), 2 (100%), 0 (0%) of stage I, II, III, IVa of the Masaoka stage respectively. Thymic carcinoma, and high stage thymoma had significantly higher proportion of bcl-2 expression than thymoma (p=0.021) and low stage thymoma (p=0.011). However, p53 showed no correlation with the histological subtypes nor with clinical aggressiveness. Bcl-2 expression appeared to be positively correlated with p53 immunoactivity (p=0.007, kappa=0.525). Conclusion: These date indicate that bcl-2 expression correlates with aggressiveness in thymic epithelial tumors, but further studies on mutation of p53 protein is necessary because bcl-2 expression appeared to be positively correlated with p53 immunoactivity.