Browsing by Author "Sayitoglu, Muge"

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    Aberrant Hypermethylation of APC Tumor Supressor Gene in Acute Leukemia Patients
    (AKAD DOKTORLAR YAYINEVI, 2017-01-01) Hatirnaz, Ozden N. G.; Firtina, Sinem; Erbilgin, Yucel; Ozbek, Ugur; Sayitoglu, Muge
    Wingless Type (WNT) signaling pathway is an evolutionarily conserved pathway that is crucial for the cell fate determination, survival and expansion of lymphocyte progenitors. It has been demonstrated that deregulated WNT signaling is one of the participating mechanism underlying lymphoid leukemogenesis. Inactivating mutations and methylation in Adenomatous Polyposis Coli (APC) gene, a negative regulator of WNT pathway, can cause ligand independent WNT pathway simulation. In this study, promoter methylation and expression of the APC gene is evaluated in childhood lymphoid and myeloid acute leukemia patients (n=118) and representative cell lines by using methylation specific PCR (MS-PCR) and real time quantitative PCR (QRT-PCR). APC gene promoter found hypermethylated in the 56\% of childhood acute leukemia patients {[}49.2\% of B-cell acute lymphoblastic leukemia (B-ALL), 62.5\% of T-cell acute lymphoblastic leukemia (T-ALL) and 64.1\% of Acute myeloid leukemia (AML)]. To evaluate the reflection of promoter methylation, APC mRNA levels were examined and found that all acute lymphoblastic leukemia subgroups have statistically lower APC expression levels compared to controls. Although there was no association with clinical parameters, promoter hypermethylation of APC gene seems to be a common epigenetic event in acute leukemia and leading to differential expression levels among different acute leukemia phenotypes.
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    Copy-number variations in adult patients with chronic immune thrombocytopenia
    (TAYLOR \& FRANCIS LTD, 2020-01-01) Yucesan, Emrah; Ng, Ozden Hatirnaz; Yalniz, Fevzi Firat; Yilmaz, Hulya; Salihoglu, Ayse; Sudutan, Tugce; Eskazan, Ahmet Emre; Ongoren, Seniz; Baslar, Zafer; Soysal, Teoman; Ozbek, Ugur; Sayitoglu, Muge; Ar, M. Cem
    Objectives Immune thrombocytopenia (ITP) is an autoimmune disease with heterogeneous background. FCGR2C mutations were defined in one third of the patients but genetic players have not been fully elucidated yet. Although childhood ITP present as benign, ITP in adulthood is chronic disease with treatment challenges. This study aimed to focus on adult ITP patients using a whole genome genotyping that is valuable approach to identify the responsible genomic regions for the disease. Methods Herein 24 adult primary-refractory for ITP patients were evaluated using HumanCytoSNP12BeadChip,Illumina. Forty-six age and sex matched healthy individuals, and ptients awith nonhematological conditions were analyzed as controls. Identified CNV regions were verified by qRTPCR. T-cell receptor beta and delta (TCRB/TCRG) clonality were assessed by heteroduplex analysis in mosaic cases. Results Several CNV losses and gains were defined (losses:2q,7q,17q,19p, and gains: 1q,2p,3q,4q,7q,10q,12p,13q,14q,15q,17p,20q,21p,22q,Xp). Mosaic changes of different sizes (0.2-17.77Mb) were identified in five patients and three of them showed clonality. CNV regions that were unique to ITP patients were identified for the first time and among these genes, those related to immune regulation, and cellular trafficking were noteworthy. Conclusion: Identified CNV regions harbor several candidate genes, the functions of which might shed light on the pathogenesis of chronic ITP.
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    Primary antibody deficiencies in Turkey: molecular and clinical aspects (Oct, 10.1007/s12026-021-09242-z, 2021)
    (HUMANA PRESS INC, 2022-01-01) Firtina, Sinem; Ng, Yuk Yin; Ng, Ozden H.; Kiykim, Ayca; Ozek, Esra Yucel; Kara, Manolya; Aydiner, Elif; Nepesov, Serdar; Camcioglu, Yildiz; Sayar, Esra H.; Gungoren, Ezgi Yalcin; Reisli, Ismail; Torun, Selda H.; Haskologlu, Sule; Cogurlu, Tuba; Kaya, Aysenur; Cekic, Sukru; Baris, Safa; Ozbek, Ugur; Ozen, Ahmet; Sayitoglu, Muge
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    PTEN and AKT1 Variations in Childhood T-Cell Acute Lymphoblastic Leukemia
    (GALENOS YAYINCILIK, 2020-01-01) Kucukcankurt, Fulya; Erbilgin, Yucel; Firtina, Sinem; Ng, Ozden Hatirnaz; Karakas, Zeynep; Celkan, Tiraje; Unuvar, Aysegul; Ozbek, Ugur; Sayitoglu, Muge
    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 low-level 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.
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    Zinc finger protein 384 (ZNF384) impact on childhood mixed phenotype acute leukemia and B-cell precursor acute lymphoblastic leukemia
    (TAYLOR \& FRANCIS LTD, 2022-01-01) Sudutan, Tugce; Erbilgin, Yucel; Hatirnaz Ng, Ozden; Karaman, Serap; Karakas, Zeynep; Kucukcankurt, Fulya; Celkan, Tiraje; Timur, Cetin; Ozdemir, Gul Nihal; Hacisalihoglu, Sadan; Gelen, Sema Aylan; Sayitoglu, Muge
    B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a heterogeneous malignancy and consists of several genetic abnormalities. Some of these abnormalities are used in clinics for risk calculation and treatment decisions. Patients with ZNF384 rearrangements had a distinct expression profile regardless of their diagnosis, BCP-ALL or mixed phenotype acute leukemia (MPAL) and defined as a new subtype of ALL. In this study, we screened 42 MPAL and 91 BCP-ALL patients for the most common ZNF384 fusions