2006 - UZ Leuven

infiltrative multilobular spindle cell proliferation with slit-like vascularspaces in these three localisations. Immunohistochemical stainsshowed positivity for CD34 and CD31 and many alpha-smooth muscleactin-positive spindle cells around the vascular spaces. There was noHerpes virus type 8 expression. The presented case is unique in twoways. First, thyroid involvement of KHE has never been described inthe literature until now. Secondly, and most remarkably, the multifocalpresentation in three anatomically distinct and separated localisationsis extremely unusual.GUETENS G., PRENEN H., DE BOECK G., HIGHLEY M., DE WEVER I.,VAN OOSTEROM A.T., DE BRUIJN E.A.: Imatinib (Gleevec ® , Glivec ® )tumour tissue analysis by measurement of sediment and by liquidchromatography tandem mass spectrometry. J. Sep. Sci, 2006; 29(3):453-459.The analysis of the signal transduction inhibitor imatinib in patienttumour tissue using LC and MS/MS is described. The anticanceragent is eluted over RP-C18 within 2 mm together with its internalstandard STI571-d8. Calibration curves were prepared in red bloodcells (RBC). For quantitative isolation of the RBC, measurement ofsediment was applied. There were no indications of signalsuppression by substances originating in the biological matrix. Thelimit of determination in tumour tissue was in the range of thoserecorded for RBC and plasma. The assay is selective and sensitive,with its robustness favouring the experimental application in clinicaloncology and its routine use in animal experiments. The LOD was 4.5ng per gram in tumour tissue.MAERTENS O., PRENEN H., DEBIEC-RYCHTER M., WOZNIAK A., SCIOTR., PAUWELS P., DE WEVER I., VERMEERSCH J., DE RAEDT T., DEPAEPE A., SPELEMAN F., VAN OOSTEROM A., MESSIAEN L., LEGIUSE.: Molecular pathogenesis of multiple gastrointestinal stromal tumorsin NF1 patients. Human Molecular Genetics, 2006; 15(6): 1015-1023.Gastrointestinal stromal tumors (GISTs) are the most commonmesenchymal tumors of the gastrointestinal tract. KIT and PDGFRAactivating mutations are the oncogenic mechanisms in most sporadicGISTs. In addition to sporadic occurrences, GISTs are increasinglybeing recognized in association with neurofibromatosis type 1 (NF1),yet the underlying pathogenic mechanism remains elusive. To gain aninsight into the mechanisms underlying GIST formation in NF1patients, we studied seven GISTs from three NF1 patients with a46