1/3. Expression and localization of scatter factor/hepatocyte growth factor in human astrocytomas.Scatter factor/hepatocyte growth factor (SF/HGF) is a pleiotropic cytokine that has been implicated in glioma invasion and angiogenesis. The SF/HGF receptor, MET, has been found to be expressed in neoplastic astrocytes as well as in endothelial cells of the tumor vasculature. Both SF/HGF and MET expression have also been described to correlate with the malignancy grade of human gliomas. However, most glioblastoma cell lines lack SF/HGF expression, raising the question of the cellular origin of SF/HGF in vivo. Using in situ hybridization, we analyzed glioblastomas, anaplastic astrocytomas, diffuse astrocytomas, pilocytic astrocytomas, and normal brain for the expression of SF/HGF mRNA. We detected strong SF/HGF expression by the majority of the tumor cells and by vascular endothelial cells in all glioblastoma specimens analyzed. Combined use of in situ hybridization with fluorescence immunohistochemistry confirmed the astrocytic origin of the SF/HGF-expressiong cells. In contrast, CD68-immunoreactive microglia/macrophages, as well as vascular smooth muscle cells reactive to alpha-smooth muscle actin, lacked SF/HGF expression. In anaplastic, diffuse, and pilocytic astrocytomas, SF/HGF expression was confined to a subset of tumor cells, and signals were less intense than in glioblastomas. In addition, we detected SF/HGF mRNA in cortical neurons. SF/HGF expression was not up regulated around necroses or at tumor margins. MET immunoreactivity was observed in GFAP-expressing astrocytic tumor cells and endothelial cells as well as in a subset of microglia/macrophages. We conclude that in vivo, both autocrine and paracrine stimulation of tumor cells and endothelium through the SF/HGF-MET system are likely to contribute to tumor invasion and angiogenesis. Lack of SF/HGF expression by most cultured glioblastoma cells is not representative of the in vivo situation and most likely represents a culture artifact.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/3. Desmoplastic infantile astrocytoma and ganglioglioma: a search for genomic characteristics.In the present study the clinical data, histology, proliferation rate, dna ploidy status and the results of TP53 mutation analysis and comparative genomic hybridization (CGH) of three typical cases of desmoplastic infantile astrocytoma and ganglioglioma are presented. Postoperative disease-free intervals of 11, 8 and 3 years were recorded and in none of the cases were radiological signs of tumor recurrence. No TP53 mutations (exons 5-8) were found. CGH analysis revealed loss of 8p22-pter in one case, while in another case gain of 13q21 was detected. In the case with the follow-up of 11 years an aneuploid dna-flow cytogram along with slightly increased MIB-1 labeling index (LI) was found. The results demonstrate little genetic instability in these low-grade lesions. dna-aneuploidy seems not to be indicative of tumor progression. It is concluded that the genetic aberrations found in desmoplastic infantile ganglioglioma differ from those encountered in common astrocytomas.- - - - - - - - - - ranking = 0.5keywords = hybridization (Clic here for more details about this article) |
3/3. Systemic cytomegalovirus infection during postoperative chemoradiotherapy for malignant astrocytoma: case report with immunohistochemistry and in situ hybridization.We report a patient with a systemic cytomegalovirus (CMV) infection, which occurred during postoperative chemoradiotherapy for a malignant astrocytoma. To our knowledge, there is no report that is especially focused on the association with a CMV infection. Interstitial pneumonia and gastrointestinal bleeding, which developed suddenly during postoperative chemoradiotherapy, resulted in the patient's death. A histopathological examination of the postmortem specimens revealed numerous "owl's eye" cells containing intranuclear inclusion bodies, which were identified as CMV by immunohistochemical examination and in situ hybridization. The premortem diagnosis of CMV infection is usually difficult, because an anti-CMV titer can be nonspecifically elevated. With immunohistochemical examination and in situ hybridization, CMV in excretory or biopsy specimens can be identified and the diagnosis of CMV infection can be established. When serious pneumonia or massive gastrointestinal bleeding occurs during postoperative chemoradiotherapy, the differential diagnosis should include the possibility of CMV infection and we recommend an immunohistochemical examination and in situ hybridization for the detection of CMV.- - - - - - - - - - ranking = 3.5keywords = hybridization (Clic here for more details about this article) |