Search

Objective: PTEN/AKT pathway deregulations have been reported to be associated with treatment response in acute leukemia. This study examined pediatric T-cell acute lymphoblastic leukemia (T-ALL) samples for PTEN and AKT1 gene variations and evaluated the clinical findings. Materials and Methods: Fifty diagnostic bone marrow samples of childhood T-ALL cases were investigated for the hotspot regions of the PTEN and AKT1 genes by targeted next-generation sequencing. Results: A total of five PTEN variations were found in three of the 50 T-ALL cases (6%). Three of the PTEN variations were first reported in this study. Furthermore, one patient clearly had two different mutant clones for PTEN. Two intronic single-nucleotide variations were found in AKT1 and none of the patients carried pathogenic AKT1 variations. Conclusion: Targeted deep sequencing allowed us to detect both lowlevel variations and clonal diversity. Low-level PTEN/AKT1 variation frequency makes it harder to investigate the clinical associations of the variants. On the other hand, characterization of the PTEN/ AKT signaling members is important for improving case-specific therapeutic strategies.

OBJECTIVE: The prominent functions of the local renin-angiotensin system (RAS) in primitive hematopoiesis further support the hypothesis that local autocrine bone marrow RAS could also be active in neoplastic hematopoiesis. The aim of this study is to examine critical RAS elements in normal CD34+ hematopoietic stem cells and multiple myeloma (MM)-related progenitor cells. METHODS: The study group comprised the total bone marrow cells (CBM) of 10 hematologically normal people, the CD34+ stem cell samples (CD34+CBM) of 9 healthy donors for allogeneic peripheral stem cell transplantation, and the CD34+ stem cell samples (CD34+MM) of 9 MM patients undergoing autologous peripheral stem cell transplantation. We searched for the gene expression of the major RAS components in healthy hematopoietic cells and myeloma cells by quantitative real-time polymerase chain reaction analysis. RESULTS: RENIN, angiotensinogen (ANGTS), and angiotensin converting enzyme-I (ACE I) mRNA expression levels of CBM were significantly higher than those in myeloma patients (p=0.03, p=0.002, and p=0.0008, respectively). Moreover, RENIN and ANGTS mRNA expression levels were significantly higher in CD34+ stem cell samples of healthy allogeneic donors compared to those in myeloma patients (p=0.001 and p=0.01). However, ACE I expression levels were similar in CD34+CBM and CD34+MM hematopoietic cells (p=0.89). CONCLUSION: Although found to be lower than in the CBM and CD34+CBM hematopoietic cells, the local RAS components were also expressed in CD34+MM hematopoietic cells. This point should be kept in mind while focusing on the immunobiology of MM and the processing of autologous cells during the formation of transplantation treatment protocols.

OBJECTIVE: T-cell acute lymphoblastic leukemia (T-ALL) is associated with recurrent chromosomal aberrations and abnormal ectopic gene expression during T-cell development. In order to gain insight into the pathogenesis of T-ALL this study aimed to measure the level of expression of 7 T-cell oncogenes (LMO2, LYL1, TAL1, TLX1, TLX3, BMI1, and CALM-AF10) in pediatric T-ALL patients. METHODS: LMO2, LYL1, TLX1, TLX3, BMI1, TAL1, and CALM-AF10 expression was measured using quantitative real-time PCR in 43 pediatric T-ALL patients. RESULTS: A high level of expression of LMO2, LYL1, TAL1, and BMI1 genes was observed in a large group of T-ALL. Several gene expression signatures indicative of leukemic arrest at specific stages of normal thymocyte development (LYL1 and LMO2) were highly expressed during the cortical and mature stages of T-cell development. Furthermore, upregulated TAL1 and BMI1 expression was observed in all phenotypic subgroups. In all, 6 of the patients had TLX1 and TLX3 proto-oncogene expression, which does not occur in normal cells, and none of the patients had CALM-AF10 fusion gene transcription. Expression of LYL1 alone and LMO2-LYL1 co-expression were associated with mediastinal involvement; however, high-level oncogene expression was not predictive of outcome in the present pediatric T-ALL patient group, but there was a trend towards a poor prognostic impact of TAL1 and/or LMO2 and/or LYL1 protooncogene expression. CONCLUSION: Poor prognostic impact of TAL1 and/or LMO2 and/or LYL1 proto-oncogene expression indicate the need for extensive study on oncogenic rearrangement and immunophenotypic markers in T-ALL, and their relationship to treatment outcome.

Objective: Despite the efficacy of the BCR-ABL tyrosine kinase inhibitor imatinib, the development of resistance against imatinib has been observed. The most important mechanisms known to cause resistance are point mutations in the ABL tyrosine kinase and the ATP domain. This study describes the use of denaturing high performance liquid chromatography (dHPLC) as a method to screen for mutations of the ABL gene.Material and Methods: We used the dHPLC based assay for the screening of ABL point mutations. Forty chronic myeloid leukemia (CML) patients who showed resistance to imatinib were screened in parallel by dHPLC and direct sequencing.Results: Nine of the 40 patients (23%) had mutations. Conclusion: dHPLC can be a useful method for pre-screening. Analyzing the mutations and monitoring (high-risk) patients can improve their prognosis and survival rate. dHPLC can potentially become a valuable tool for regular testing of patients in the future.

OBJECTIVE: Despite the efficacy of the BCR-ABL tyrosine kinase inhibitor imatinib, the development of resistance against imatinib has been observed. The most important mechanisms known to cause resistance are point mutations in the ABL tyrosine kinase and the ATP domain. This study describes the use of denaturing high performance liquid chromatography (dHPLC) as a method to screen for mutations of the ABL gene. METHODS: We used the dHPLC based assay for the screening of ABL point mutations. Forty chronic myeloid leukemia (CML) patients who showed resistance to imatinib were screened in parallel by dHPLC and direct sequencing. RESULTS: Nine of the 40 patients (23%) had mutations. CONCLUSION: dHPLC can be a useful method for pre-screening. Analyzing the mutations and monitoring (high-risk) patients can improve their prognosis and survival rate. dHPLC can potentially become a valuable tool for regular testing of patients in the future.