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61 Summary Wilms' tumor gene 1 (WT1) is highly expressed in acute leukemia and other hematological malignancies. It has been therefore suggested as a potential universal marker of minimal residual disease (MRD), particularly in patients with acute myeloid leukemia (AML). Due to controversial results of some of the studies, the role of WT1 in MRD follow-up and WT1 prognostic significance remain unclear. WT1 protein is produced in more than 36 different isoforms. These variants have distinct, partially overlapping functions and their ratio is supposed to influence the final effect of WT1. However, despite the increasing number of studies, the clinical impact of WT1 and its isoforms in acute leukemia have not yet been elucidated. We established a unique qPCR method to assess the expression pattern of the main 4 WT1 isoforms. Using this method, we determined the ratio of WT1 variants in the samples of patients with AML, myelodysplastic syndrome (MDS) and healthy controls. Our data showed that this pattern can distinguish among particular hematological malignancies, but lacks a prognostic significance. Within our international study group we determined the prognostic significance of total WT1 expression in childhood AML. Based on our results of a large cohort of patients we can conclude that WT1 expression at...

Testicular germinal tumors (TGCT) are relatively rare solid tumors in adults. Even so, they affect more than 700 men a year in the Czech Republic, mostly young patients aged 18- 45 years. A large number of patients are curable by a combination of surgery and chemotherapy, yet about 50 men a year in the Czech Republic succumb to this tumor, in the vast majority of cases due to the development of resistance to chemotherapy containing cisplatin. The rare occurrence and high curability are probably the cause of infrequent molecular and clinical studies carried out in these tumors, and our understanding of the biological processes leading to primary tumor development and the development of cisplatin resistance (CDDP) is still limited. At present, no specific molecular markers that could be used as prognostic or predictive factors and improve patient stratification or treatment tailoring are available in TGCT management. In this work, we studied the molecular-genetic background of TGCT development and CDDP resistance at several levels. To comprehensively study the development of cisplatin resistance, we prepared and analyzed CDDP-exposed TGCT cell lines. Long-term exposure to CDDP increased resistance 10-fold in the NCCIT cell line, while no significant resistance was achieved with Tera-2. The...