Merkel-Zell-Karzinom

Das Merkel-Zell-Karzinom (kutanes neuroendokrines Karzinom) ist ein seltener, hochgradig maligner, neuroendokriner Hauttumor. Es entwickelt sich im typischen Fall als derber, schnell wachsender, mit der Dermis verbundener Knoten, der histologisch durch monomorphe runde Zellen mit schmalem Zytoplasmasaum und Kernatypien gekennzeichnet ist. Die Tumorzellen exprimieren die Zytokeratine 8, 18, 19, 20, Neurofilament, Synaptophysin, Chromogranin und neuronenspezifische Enolase. Der Erkrankungsverlauf ist durch eine ausgepr?gte Neigung zu Lokalrezidiven (25–77%) und Lymphknotenmetastasen (ca. 50%) charakterisiert. Die 5-Jahres-überlebensrate betr?gt 30–74%. Merkel-Zell-Karzinome sind ausgesprochen strahlensensibel. Neben den chirurgischen Verfahren sollte deshalb die Strahlentherapie in allen Erkrankungsstadien in das Behandlungskonzept einbezogen werden. Wir berichten über 4 F?lle mit unterschiedlichen Verl?ufen, anhand derer das gesamte Krankheitsbild übersichtsartig mit Empfehlungen zur raschen Diagnosefindung und effektiver Therapie er?rtert wird.     

Fanconi's anemia treated by allogeneic marrow transplantation

Eight patients with Fanconi's anemia were given cyclophosphamide alone (seven patients) or combined with procarbazine and antithymocyte globulin (one patient) followed by marrow grafts from HLA-identical siblings. All patients had engraftment. Seven developed acute and three chronic graft-versus-host disease (GVHD). Three patients died with GVHD and infectious complications (days 19, 56, and 82) and one with an intracerebral hemorrhage (day 540). Four patients are surviving 647- 3435 days after grafting, two are well, and two have chronic GVHD that is improving. These results show that Fanconi's anemia can be treated successfully by allogeneic marrow transplantation.     

The Tie receptor tyrosine kinase is expressed by human hematopoietic progenitor cells and by a subset of megakaryocytic cells

Growth factor receptors in human hematopoietic progenitor cells have become the focus of intense interest, because they may provide tools for the monitoring, enrichment, and expansion of stem cells. We have shown earlier that the Tie receptor tyrosine kinase is expressed in erythroid and megakaryoblastic human leukemia cell lines, in the blood islands of the yolk sac, and in endothelial cells starting from day 8.0 of mouse development. Here, the expression of Tie was studied in human hematopoietic cells of various sources. Peripheral blood mononuclear cells were Tie-. However, a large fraction of CD34+ cells from umbilical cord blood (UCB) and bone marrow (BM) expressed tie protein and mRNA. On average, 64% of the fluorescence-activated cell sorting- gated UCB CD34+ cells including CD38- cells and a fraction of cells expressing low levels of c-Kit were Tie+. Also, 30% to 60% of BM CD34+ cells were Tie+, including most of the BM CD34+CD38-, CD34+Thy-1+, and CD34+HLA-DR- cells. Under culture conditions allowing myeloid, erythroid, and/or megakaryocytic differentiation, purified UCB CD34+ cells lost Tie mRNA and protein expression concomitantly with that of CD34; however, a significant fraction of cells expressed Tie during megakaryocytic differentiation. These data suggest that, in humans, the Tie receptor and presumably its ligand may function at an early stage of hematopoietic cell differentiation.     

Identification of a cellular polypeptide that distinguishes between acute lymphoblastic leukemia in infants and in older children

We analyzed the polypeptide pattern of leukemic cells of infants and older children with acute lymphoblastic leukemia (ALL), using two- dimensional polyacrylamide gel electrophoresis (PAGE). Patterns were analyzed for the occurrence of a previously detected cytosolic polypeptide, designated L3. Quantitative analysis of L3 in 12 infants and 91 older children with non-T ALL indicated lack of expression of polypeptide L3 in leukemic cells of infants which, in most cases, expressed HLA-DR and CD19 and lacked CD10. Quantitative analysis of L3 in relation to cell surface marker expression revealed that L3 was limited in its occurrence to non-T ALL and was not coordinately expressed with any of the surface markers included in the study. Among patients in the HLA-DR-positive, CD19-positive, and CD10-negative group, different levels of polypeptide L3 were observed between infants and older children. These results indicate differences in leukemic cell constituents between infants and older children with ALL and an otherwise similar cell surface marker phenotype.