Lin Pj

Expression of OCT4 in the primary germ cell tumors and thymoma in the mediastinum.

Primary germ cell tumors (GCTs) and thymoma are both located in the anterior mediastinum. A previous study has postulated that octamer binding transcription factor (OCT4) is a nuclear transcription factor that is expressed in pluripotent embryonic germ cells. This study examined OCT4 expression in GCTs and thymoma originating from the mediastinum. A retrospective study included 46 consecutive patients with GCTs conducted between 1983 and 2005, and 22 consecutive thymoma in the mediastinum whose tumors had been surgically excised. The 46 primary GCTs in mediastinum included teratoma (n=27; 58.7%), seminoma (n=10; 21.7%), yolk sac tumor (n=6; 13%), embryonal carcinoma (n=1; 2.1%), and mixed GCTs (n=2; 4%; one consisted of teratoma and yolk sac tumor, and the other teratoma, yolk sac tumor, and seminoma); and 22 thymoma including World Health Organization type A (n=3, 13.6%), type AB (n=4, 18.2%), type B1 (n=6, 27.3%), type B2 (n=4, 13.6%), and type B3 (n=5, 22.7%). Each tumor was examined with hematoxylin and eosin staining, and with antibodies to OCT4. All 10 seminoma cases, 1 embryonal carcinoma case, and 1 mixed GCT case containing seminoma were immunopositive for OCT4. On the other hand, the 22 thymoma, 6 yolk sac tumor, 27 teratomas, and 1 case with mixed GCT without component of seminoma were immunonegative for OCT4. We conclude that immunostaining with antibodies to OCT4 is a useful diagnostic tool in the identification of seminomas and primary embryonal carcinomas in GCTs originating from the mediastinum.

The Fas-mediated apoptotic pathway in cardiac myxoma.

Cardiac myxoma is the most common primary tumor of the heart. The existence of apoptosis in cardiac myxoma has been demonstrated. The purpose of this investigation was to elucidate the pathway of apoptosis and the cell cycle in cardiac myxomas. This study had 2 parts: investigation of a cultured cardiac myxoma cell line and the analysis of data from 20 patients with cardiac myxoma that was surgically excised. Apoptosis signal transduction was determined by assessing DNA fragmentation, Fas ligand (FasL), Fas, tumor necrosis factor-α (TNF-α), caspase-3, and terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) assay through immunohistochemical stain, quantitative reverse transcriptase— polymerase chain reaction (RT-PCR), and Western blot analysis. The patient population consisted of 12 (60%) women and 8 (40%) men with a mean age of 46 years (range = 32-64 years). All cases of myxoma were sporadic myxomas rather than familial. Clinical presentations included asymptomatic (26%), dyspnea (44%), stroke (9%), chest pain (9%), and fever (11%). All myxomas were located in the left atrium. Pathological scores for inflammation, cellularity, calcification, and thrombosis were not related to myxoma location or clinical events. In cardiac myxoma, apoptosis documented by TUNEL (70.9% ± 17.6%) and the caspase-3 (66.5% ± 32.5%) final common pathway is characterized by the extrinsic Fas/ FasL dependent pathway (positive stained 70.9% ± 19.2%; 26.0% ± 17.2%, respectively), but not the intrinsic pathway. The RT-PCR and Western Blot analysis (Fas/FasL, TNF-α, caspase-3, and apoptosis) of the cardiac myxoma and cultured cardiac myxoma cells confirmed the immunochemical results. The extrinsic Fas/FasL-dependent apoptosis pathways in cardiac myxomas were proved by both RNA and protein levels.

Caspase-3-dependent apoptosis in cardiac myxoma: not associated with human papillomavirus or Epstein–Barr virus

Cardiac myxoma is the most common tumor of the heart, has a variable clinical presentation and immunohistochemical profile. Viral infections, such as herpes simplex virus, human papillomavirus (HPV), and Epstein–Barr virus (EBV), may play an important role in the causes of cardiac myxoma. This investigation will demonstrate caspase-3-dependent apoptosis in cardiac myxoma without HPV or EBV infection. This study included 15 patients with cardiac myxoma, who were treated with surgical excision of the lesion. Data were collected on detailed clinical parameters. Terminal deoxynucleotidyl transferase nick-end labeling assay, electrophoresis, and caspase-3 immunohistochemical studies were performed to characterize apoptosis. Genechip containing 39 subtypes was used to elucidate HPV; and polymerase chain reaction to detect LMP-1 gene of EBV. The patient population comprised of eight (53%) women and seven (47%) men. The mean age of patient participants was 45 years, with an age range of 30–70 years. All patient cases were sporadic myxomas rather than familial myxomas. The patient presentations included dyspnea (53%), asymptomatic (27%), stroke (7%), chest pain (7%), and fever (7%). All lesions were located in the left atrium. The individual patient cases of myxoma did not differ in location or clinical event in terms of pathological scores, such as vascular proliferation, inflammation, cellularity, hyaline, calcification, or thrombosis. Cardiac myxoma is characterized by apoptosis through caspase-dependent pathway. HPV or EBV was not detected in any of the study patient samples. In conclusion, no viral genomes of HPV or EBV were detected in these 15 patients. This study demonstrates that caspase-3-dependent apoptosis in cardiac myxoma is not dependent on concurrence of previous HPV and/or EBV infection.