Clinical and immunohistochemical study of eight cases with thymic carcinoma

BACKGROUND: Thymic carcinoma is a rare neoplasm with extremely poor prognosis. To evaluate the biological characteristics of thymic carcinoma, we reviewed 8 patients. METHODS: There were 2 men and 6 women: ages ranged from 19 to 67 years old (mean 54.8 years). None of these patients had concomitant myasthenia gravis and pure red cell aplasia. No patient had stage I disease, 1 stage II, 5 stage III, and 2 stage IV. The pathologic subtypes of thymic carcinoma included 5 squamous cell carcinomas, 1 adenosquamous cell carcinomas, 1 clear cell carcinoma, and 1 small cell carcinoma. Immunohistochemical study was performed using antibodies against p53, bcl-2, Ki-67, carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), nm23-H1, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF-2) and factor VIII. RESULTS: Curative resection could be done in 4 patients (50%). Our data indicates a trend toward an association between complete resection and patient survival. Expression of p53, bcl-2, CEA, EMA, nm23-H1, VEGF and FGF-2 was detected in 5/8, 3/8, 4/8, 5/8, 6/8, 5/8 and 3/8, respectively. Mean Ki-67 labeling index and microvessel density was 7.01 and 34.36 (per 200× field), respectively. When compared with our previous studies, immunohistochemical staining of these proteins in thymomas, the expression rates of these proteins in thymic carcinomas were higher than those in thymomas. CONCLUSIONS: In this small series, it is suggested that a complete resection suggests a favorable result. Immunohistochemical results reveal that the expression of these proteins might indicate the aggressiveness of thymic carcinoma

Keratinocyte progenitor cells reside in human subcutaneous adipose tissue.

The differentiation of adipose-derived stem cells (ASCs) towards epithelial lineages has yet to be demonstrated using a standardized method. This study investigated whether keratinocyte progenitor cells are present in the ASC population. ASCs isolated from subcutaneous adipose tissue were cultured and examined for the expression of the keratinocyte progenitor markers p63 and desmoglein 3 (DSG3) by immunofluorescence microscopy and flow cytometry. In addition, p63 and DSG3 expression levels were assessed before and after differentiation of ASCs into adipocytes by real-time PCR and western blot analysis, as well as in subcutaneous adipose tissue by real-time reverse transcriptase polymerase chain reaction. Both markers were expressed in ASCs, but were downregulated after the differentiation of ASCs into adipocytes; p63-positive cells were also detected in subcutaneous adipose tissue. ASCs co-cultured with human fibroblasts and incubated with all-trans retinoic acid and bone morphologic protein 4 showed an upregulation in DSG3 level, which was also increased in the presence of type IV collagen. They also showed an upregulation in cytokeratin-5 level only in the presence of type IV collagen. These results provide the demonstration that keratinocyte progenitor cells reside in subcutaneous adipose tissue

Downregulation of keratinocyte marker expression in ASCs after their differentiation into adipocytes.

<p>The expression of p63 and DSG3 was measured by (a) quantitative real-time PCR (relative to glyceraldehyde-3-phosphate dehydrogenase) and (b) by western blotting (relative to β-actin) in undifferentiated ASCs and those that had differentiated into adipocytes. Both markers were expressed at lower levels after differentiation.</p

Keratinocyte marker expression in ASCs.

<p>ASCs cultured in chambered slides were fixed and labeled with antibodies against p63 and DSG3. Undifferentiated ASCs and NHEKs (positive control) expressed (a) p63 and (b) DSG3 (both visible by green fluorescence). Scale bars, 20 μm. (c) The expression of p63 and DSG3 in ASCs and NHEKs was detected by flow cytometry.</p