The origin of the neoplastic stromal cell in giant cell tumor of bone.

Fibroblastlike stromal cells, which are always present as a component of giant cell tumor of bone (GCT), can be observed in both in vivo and cultured cell samples. Although they are assumed to trigger the cancer process in GCT, the histogenesis of GCT stromal cells is poorly understood. It is known that mesenchymal stem cells (MSCs) can develop to osteoblasts. Evidence has been presented that GCT stromal cells can also develop to osteoblasts. A connection between MSCs and GCT stromal cells was sought by using 2 different laboratory approaches. First, immunohistological analyses revealed that some of the same markers, detected by the SH2, SH3, and SH4 antibodies and the CD166 antigen, were found in GCT stromal cells as in the first developmental stages of osteoblast differentiation from the initial MSCs. These immunohistological findings could be confirmed by reverse transcriptase polymerase chain reaction. Second, cellular differentiation by morphology and lineage-specific staining offered evidence that not only osteoblasts, but also chondroblasts and adipocytes, could be cultured from stromal cells. The presented double approach indicates that GCT stromal cells can originate from MSCs.

Histological findings in ruptured aneurysms treated with GDCs: six examples at varying times after treatment.

BACKGROUND AND PURPOSE: A novel plastic embedding approach was used to histologically evaluate inflammatory changes and scar formation over time and to better visualize the mesh attenuation within the aneurysm lumen of acutely ruptured aneurysms after treatment with GDCs. METHODS: Autopsies were performed on six patients with acute subarachnoid hemorrhage who had died between 5 and 272 days after GDC treatment. The aneurysms containing the platinum coils were embedded in plastic along with the intact parent vessels, were sliced, and were ground to a thickness of 5 to 10 micro m. In addition, 250- micro m-thick sections were prepared. Histologic examinations were performed. Three exemplary cases representing the time lapse from treatment to death are discussed in detail. RESULTS: At the three exemplary time periods (5, 13, and 272 days) after coiling, a continuing healing process could be observed. At 5 days after placement of GDCs, a blood clot consisting of erythrocytes and fibrin was found throughout the cavity. Thirteen days after the procedure, large foamy macrophages were observed near the coils in the aneurysm cavity. Two hundred seventy-two days after the intervention, scar formation within the aneurysm appeared to be completed, with vascularized connective tissue filling the cavity and embedding the coils. Large foreign body giant cells were found adjacent to the coils. A layer of long slender cells, resembling endothelium, sealed the aneurysm neck. CONCLUSION: We postulate that within days after GDC treatment, blood clotting and thrombus formation prevent rebleeding and that solid scar formation covered by a layer of long slender cells, resembling endothelium, seals the aneurysm over time.

Prognostic significance of drug-regulated genes in high-grade osteosarcoma.

About 25-45% of patients with high-grade osteosarcoma poorly respond to chemotherapy with an increased risk of relapse and the development of metastasis. Therefore, the aim of this study was the evaluation of the prognostic value of eight previously identified drug-regulated candidate genes on osteosarcoma therapy outcome. Gene expression of 8 candidate genes was analyzed in 35 formalin-fixed, paraffin-embedded, laser-microdissected osteosarcoma biopsies. The prognostic value of these genes was evaluated by the correlation of gene expression with therapy outcome, overall survival and event-free survival in univariate and multivariate analysis. Upon univariate analysis, the expression of MALAT-1, IMPDH2, FTL and RHOA significantly correlated with response to chemotherapy. Expression of all four genes was increased in the poor responder group. Upon multivariate analysis, IMPDH2 maintained its independent prognostic value (P=0.025). Concerning the overall survival of the patients, we observed a significant association with the expression of FTL, PHB, ATAD2, ACTN1 and RRM2 as well as lactate dehydrogenase serum levels. In the subgroups of patients with high expression of these genes and those with elevated lactate dehydrogenase levels, the mean overall survival was decreased 1.7-, 1.9-, 2.2-, 2.4-, 1.5- and 4.5-fold, respectively. Except RRM2, all genes and lactate dehydrogenase serum levels remained significant in the multivariate analysis. In addition, the event-free survival was significantly decreased in the subgroups of patients with high FTL, ATAD2 and IMPDH2 expression (1.8-, 6.3- and 2.4-fold, respectively). These data demonstrate that among the identified genes are valuable markers for the prediction of osteosarcoma therapy outcome. Especially IMPDH2 and FTL are promising candidates for the stratification of osteosarcoma patients into low- and high-risk groups. Owing to their involvement in drug action these genes may further be potential targets for the modulation of drug sensitivity.

A scanning electron microscopy-based approach to quantify resorption lacunae applied to the trabecular bone of the femoral head.

Resorption lacunae (RL) are discussed as stressors that can increase the risk of mechanical failure in a trabecular network. Quantification of RL has previously been described through the parameter eroded surface/bone surface (ES/BS) as established by light microscopy (LM) analysis, but the results have been inconsistent and contradictory. Using scanning electron microscopy (SEM), a new study design for quantitative evaluation is introduced. To test its applicability a pilot study was executed with trabecular bone dissected from a femoral head of 28 autopsy subjects (14 female and 14 male). A 2.4 x 2.8 x 1.0 mm sample was excised 1.5 cm below the joint surface of each specimen in coronal medial slices of the femoral head and examined. A virtual grid with 1050 squares superimposed over the generated SEM image allowed determination of the ratio of squares containing RL to squares with an unaffected trabecular surface (RL/U). Classical ES/BS was assessed in parallel sections of the samples. The SEM, and to a lesser extent the qualitative different LM analysis, indicated a gender independent predominance of RL in subjects older than 50 years. This pilot study suggests that the new study design could be useful for acquiring quantitative RL data.

Evaluation of the predictive value of Her-2/neu gene expression on osteosarcoma therapy in laser-microdissected paraffin-embedded tissue.

Histologic response to chemotherapy is currently the strongest prognostic factor in high-grade osteosarcoma, but it can only be assessed after several weeks of therapy. Thus, detection of chemosensitivity at the time of diagnosis would be of great clinical importance. The expression of the proto-oncogene Her-2/neu has been shown to be of predictive value in breast cancer and has also been considered as prognostic marker for osteosarcomas, but reports of mainly immunohistochemical studies are controversial. Therefore, the aim of this study was to investigate Her-2/neu gene expression in laser-microdissected osteosarcoma cells. Laser microdissection enables the precise isolation of morphological defined cells from archival tissue specimens and is in combination with the highly sensitive real-time RT-PCR technique a valuable tool for cell-specific analysis of gene expression. Through optimization of current protocols, we could show that this technique can be successfully applied on formalin-fixed, paraffin-embedded and decalcified osteosarcoma tissue with high sensitivity and reproducibility. In all 17 osteosarcoma biopsies analyzed, we could detect Her-2/neu gene expression. Expression correlated significantly with the response to preoperative chemotherapy, which was assessed histologically according to the six-grade scale of Salzer-Kuntschik. Risk assessment on the basis of increased Her-2/neu gene expression matched the histologic findings in 16 out of 17 cases (94%). These data demonstrate the reliability of laser microdissection in the analysis of gene expression and suggest a possible role of Her-2/neu as prognostic marker for therapy outcome in osteosarcomas.