[Chordoma-An update]. / Chordome ­ Ein Update.

Chordomas are rare malignant tumors of the axial skeleton with notochordal differentiation. From a morphological point of view, chordomas display a broad spectrum ranging from the classical, conventional form not otherwise specified (NOS) to forms with hepatoid or renal carcinoma-like differentiation or even poorly or dedifferentiated variants. The detection of brachyury is highly characteristic, though not exclusive. The morphological differential diagnosis from a benign notochordal tumor (BNCT) requires integration of imaging since BNCT is limited to the vertebral bodies and is not osteolytic. Targeted therapy is a current research focus and cell lines as in vitro models are a precondition for the establishment and validation of this approach.

[H3F3A mutated multicentric giant cell tumor of bone : A very rare primary bone disease]. / H3F3A-mutierter multifokaler Riesenzelltumor des Knochens : Eine äußerst seltene primär ossäre Erkrankung.

This article presents the case of a metachronic multicentric giant cell tumor of bone (GCTB). The patient obtained his first diagnosis of GCTB in the left humerus at the age of 47 years. Furthermore, he suffered from a GCTB in the head of his 4th left metacarpal bone and from a recurrence of the latter. All tumors carried the characteristic H3F3A mutation, which was proven by Sanger sequencing and a mutation specific antibody. The case is the first description of a multicentric H3F3A mutated GCTB.

Restoring functional neurofibromin by protein transduction.

In Neurofibromatosis 1 (NF1) germ line loss of function mutations result in reduction of cellular neurofibromin content (NF1+/-, NF1 haploinsufficiency). The Ras-GAP neurofibromin is a very large cytoplasmic protein (2818 AA, 319 kDa) involved in the RAS-MAPK pathway. Aside from regulation of proliferation, it is involved in mechanosensoric of cells. We investigated neurofibromin replacement in cultured human fibroblasts showing reduced amount of neurofibromin. Full length neurofibromin was produced recombinantly in insect cells and purified. Protein transduction into cultured fibroblasts was performed employing cell penetrating peptides along with photochemical internalization. This combination of transduction strategies ensures the intracellular uptake and the translocation to the cytoplasm of neurofibromin. The transduced neurofibromin is functional, indicated by functional rescue of reduced mechanosensoric blindness and reduced RasGAP activity in cultured fibroblasts of NF1 patients or normal fibroblasts treated by NF1 siRNA. Our study shows that recombinant neurofibromin is able to revert cellular effects of NF1 haploinsuffiency in vitro, indicating a use of protein transduction into cells as a potential treatment strategy for the monogenic disease NF1.

U-CH17P, -M and -S, a new cell culture system for tumor diversity and progression in chordoma.

Chordoma is a rare bone tumor with a known intrinsic heterogeneity. Here, we address this tumor heterogeneity in a new cell culture model for tumor diversity and progression in chordoma. The three cell lines U-CH17P, U-CH17M, and U-CH17S were established from a primary sacral chordoma and its derived metastases, a soft tissue and a skin metastasis, respectively. The lesions had divergent differentiation patterns which are conserved in the derived cell lines making them a suitable in vitro model for the analysis of tumorigenesis in chordoma. A common feature of the three cell lines is the expression of typical chordoma markers, such as Brachyury, vimentin, cytokeratins, EMA and S100 protein. A comparison of the genomic aberrations by array comparative genomic hybridization of the cell lines and the corresponding parental tumor tissues revealed that the precursor cells of U-CH17P, U-CH17M and U-CH17S were already present in the primary tumor. Therefore, we show that clonal diversity of this chordoma exists in the primary tumor and that not all of these subclones tend to metastasize. All cell lines had a CDKN2A loss. A comparison of the gene expression profiles of the cell lines revealed significant differences in the expression of several genes like MAGEC2 and SEMA6A known to be associated with the tendency to metastasize or proliferation and migration. Since the underlying mechanisms of tumor progression in chordoma are still largely unclear, the three U-CH17 cell lines are a suitable in vitro model for elucidating chordoma oncobiology.

Low-dose antithymocyte globulin enhanced the efficacy of tacrolimus and mycophenolate for GVHD prophylaxis in recipients of unrelated SCT.

We performed a retrospective analysis of the outcome of 197 consecutive unrelated donor transplant recipients who received GVHD prophylaxis either TM regimen (tacrolimus and mycophenolate) (121 patients) or TM/ATG-G regimen (TM with low-dose antithymocyte globulin (ATG) of 4.5 mg/kg, ATG-G, Genzyme) (76 patients). Cumulative incidences of grade II-IV acute GVHD for the TM and TM/ATG-G cohorts were 49% and 61% (P=0.11) and grade III-IV acute GVHD for the TM and TM/ATG-G cohorts were 27% and 14% (P=0.02), respectively. There was no difference in the incidence of relapse or disease progression between TM and TM/ATG-G-16% and 23% (P=0.64). TM/ATG-G cohort had lower incidence of non-relapse mortality (NRM; 37% vs 20%, P=0.01), chronic GVHD (56% vs 43%, P<0.001) and more favorable global chronic GVHD severity (P<0.001). Univariate analyses showed improved OS and PFS of patients who received TM/ATG-G. Multivariate analysis confirmed TM/ATG-G had a favorable influence on OS (P=0.05) but not on PFS (P=0.07). We concluded that low-dose ATG of 4.5 mg/kg given in conjunction with TM improved GVHD prophylaxis without increased risk of relapse. Lower NRM, lower incidence and severity of chronic GVHD could potentially improve survival.

Partial Blindness to Submicron Topography in NF1 Haploinsufficient Cultured Fibroblasts Indicates a New Function of Neurofibromin in Regulation of Mechanosensoric.

Cells sense physical properties of their extracellular environment and translate them into biochemical signals. In this study, cell responses to surfaces with submicron topographies were investigated in cultured human NF1 haploinsufficient fibroblasts. Age-matched fibroblasts from 8 patients with neurofibromatosis type 1 (NF1(+/-)) and 9 controls (NF1(+/+)) were cultured on surfaces with grooves of 200 nm height and lateral distance of 2 µm. As cellular response indicator, the mean cell orientation along microstructured grooves was systematically examined. The tested NF1 haploinsufficient fibroblasts were significantly less affected by the topography than those from healthy donors. Incubation of the NF1(+/-) fibroblasts with the farnesyltransferase inhibitor FTI-277 and other inhibitors of the neurofibromin pathway ameliorates significantly the cell orientation. These data indicate that NF1 haploinsufficiency results in an altered response to specific surface topography in fibroblasts. We suggest a new function of neurofibromin in the sensoric mechanism to topographies and a partial mechanosensoric blindness by NF1 haploinsufficiency.