Mutation patterns and clonal evolution in myeloproliferative neoplasms

In this thesis, a fast and easy method for the analysis of the clonal hierarchy on single cell level was established. The method was then compared to the already well-established colony progenitor assay to find the optimal method for the analysis of the clonal evolution in CML and MPN. Mutational screenings with NGS detected somatic mutations in chronic myeloid leukemia (CML) and BCR::ABL1 negative myeloproliferative neoplasms (MPN) followed by experiments for the identification of clonal architecture of the discovered mutations. Further, a case report of a chronic neutrophilic leukemia (CNL) patient presents the necessity of clonal analysis regarding choice of treatment. Mutation analyses of the CML cohort revealed that epigenetic related genes were predominantly detected as additional mutations in BCR::ABL1 positive patients. Further DNMT3A was often detected as a preleukemic event. Most common additional mutations next to JAK2V617F in MPN patients were detected in epigenetic genes especially in TET2. JAK2 as well as TET2 mutations were identified as the primary clone, however the acquisition order has no influence on the clinical phenotype. The clonal analysis of the CNL patient presented a clonal hierarchy of two compound CSF3R mutations with a transmembrane proximal CSF3RT618I and a truncation mutation CSF3RQ749X where CSF3RT618I was identified as the primary clone. A therapy decision to the proximal membrane sensitive TKI ruxolitinib led to the suppression of the CSF3RQ749X and a complete hematologic remission. Single cell analysis contributes to the understanding of clonal architecture in myeloid malignancies. The research of mutation order provides information regarding the occurrence of preleukemic events and accumulation of mutations leading to cancer progression. The CNL case report showed that the knowledge of the clonal hierarchy can be helpful in the targeted therapy decision, and it can contribute to clinical success.