Browsing by Author "Firtina, Sinem"

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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.
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
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.