Andreas Hochhaus

Early reduction of BCR-ABL mRNA transcript levels predicts cytogenetic response in chronic phase CML patients treated with imatinib after failure of interferon alpha

The degree of tumor load reduction as measured by cytogenetic response is an important prognostic factor for chronic myelogenous leukemia (CML) patients on therapy. We sought to determine whether BCR-ABL transcript levels can predict chromosomal response. Residual disease was evaluated in 120 CML patients in chronic phase (CP) treated with the selective tyrosine kinase inhibitor imatinib after resistance or intolerance to interferon α (IFN). Median time of therapy was 401 days (range 111–704). BCR-ABL and total ABL transcripts were measured in 486 peripheral blood (PB) specimens with a real time RT-PCR approach using fluorescent-labeled hybridization probes (LightCycler technology) and results were expressed as the ratio BCR-ABL/ABL. Cytogenetic response was determined in 3-monthly intervals: From 101 evaluable patients, 42 achieved a complete (CR, 0% Philadelphia chromosome (Ph)- positive metaphases), 18 a partial (PR, 1–34% Ph+), 13 a minor (MR, 35–94% Ph+), and 26 no response (NR, >94% Ph+). All PB samples were RT-PCR positive. The proportion of Ph+ metaphases and simultaneous BCR-ABL/ABL ratios correlated with ru2009=u20090.74, Pu2009<u20090.0001. In order to investigate whether early molecular analysis may predict cytogenetic response, quantitative RT-PCR data obtained after 1 and 2 months of therapy were compared with cytogenetic response at 6 months. BCR-ABL/ABL ratios after 1 month were not predictive, but results after 2 months correlated with the consecutive cytogenetic response (Pu2009=u20090.0008). The probability for a major cytogenetic response was significantly higher in patients with a BCR-ABL/ABL ratio <20% after 2 months of imatinib therapy. We conclude that: (1) quantitative determination of residual disease with real time RT-PCR is a reliable and sensitive method to monitor CML patients on imatinib therapy; (2) BCR-ABL/ABL ratios correlate well with cytogenetic response; (3) in IFN-pretreated patients all complete responders to imatinib have evidence of residual disease with the limited follow-up available; and (4) cytogenetic response at 6 months of therapy in CP patients is predictable with real time RT-PCR at 2 months.

Occurrence of additional chromosome aberrations in chronic myeloid leukemia patients treated with imatinib mesylate

Occurrence of additional chromosome aberrations in chronic myeloid leukemia patients treated with imatinib mesylate

Molecular characterization of EZH2 mutant patients with myelodysplastic/myeloproliferative neoplasms

Mutations in the epigenetic regulator gene EZH2 are frequently observed in patients with myelodysplastic/myeloproliferative neoplasms (MDS/MPN; 10–13%) and are associated with a poor outcome. To gain more insight into EZH2 pathology, we sought to genetically characterize a cohort of 41 EZH2-mutated MDS/MPN patients using targeted deep next-generation sequencing (NGS), colony-forming progenitor assays and transcriptome analysis. Stable short hairpin RNA (shRNA)-mediated downregulation of EZH2 was performed in MDS-derived F-36P, MOLM-13 and OCI-M2 cells to study EZH2-specific changes. Targeted NGS revealed a complex pattern of mutations with a total of 190 individual mutations. EZH2 mutations frequently co-occur with TET2 (58%), RUNX1 (40%) and ASXL1 (34%) mutations. Colony assays indicated EZH2 mutations to be mostly early events in leukemogenesis and showed a complex mutational hierarchy. Gene expression data revealed a number of differently expressed genes between EZH2 wild-type and mutant patients including known EZH2 targets. Comparison of patient transcriptome to EZH2-downregulated cell line data revealed several genes as novel EZH2 targets, showing opposite as well as unidirectional regulation between cell lines and patients. Some genes, such as CXXC5, ETS1 and VAV3 have previously been implied to have a role in leukemogenesis. Their precise role in MDS/MPN needs to be further investigated.

Modernes Management der chronischen myeloischen Leukämie

ZusammenfassungLang andauernde, behandlungsfreie Remissionen bei einer steigenden Patientenzahl verstärken die Hoffnung auf eine Heilbarkeit der chronischen myeloischen Leukämie (CML). Entscheidend ist ein konsequentes zytogenetisches und molekulares Follow-up der CML-Patienten mit standardisierten Methoden, um den Remissionsstatus regelmäßig zu überprüfen.

Treatment optimization of newly diagnosed BCR-ABL positive patients with chronic myeloid leukemia (CML) in chronic phase with nilotinib vs. nilotinib plus interferon a induction and nilotinib or interferon a maintenance therapy: Interim analysis of the TIGER (CML V) study

T cell stimulation with different cytokines results in distinct phenotypes and cytotoxic activity of CD19-specific CART cells

Erkrankungen des Blutes

Die hamatopoetischen Stammzellen sind charakterisiert durch die Fahigkeit zur Selbsterneuerung und Differenzierung in Progenitorzellen (Vorlauferzellen). Von diesen Vorlauferzellen stammen alle zellularen Bestandteile des Blutes ab. Die beim Erwachsenen im Knochenmark vorkommende pluripotente hamatopoetische Stammzelle steht somit am Beginn der Entwicklung aller hamatopoetischen Reihen (lymphozytar, myeloisch, erythrozytar und megakaryozytar). Die Proliferation und die Differenzierung dieser Zellen werden unter anderem durch das komplexe Zusammenspiel von Wachstumsfaktoren (Zytokinen) sowie von Zell-Zell-und Zell-Matrix-Interaktionen reguliert. Im Folgenden werden die zugrunde liegenden pathophysiologischen Konzepte dargestellt.