Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 11 2 2017 04 03 114 120 EN Farhad Zaker Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran. AND Dept. of Haematology, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran Nahid Nasiri Dept. of Haematology, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran Naser Amirizadeh Blood transfusion research center, High institute for education and research in Transfusion Medicine, Tehran, Iran Seyed Mohsen Razavi Hematology and Oncology Department, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran Marjan Yaghmaie Hematology, Oncology and Stem cell Transplantation Research Center, Tehran University of Medical Science, Tehran, Iran Ladan Teimoori-Toolabi Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran Ali Maleki Dept of Haematology, School of Allied Medicine, Tehran University of Medical Sciences, Tehran, Iran Masoumeh Bakhshayesh Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran 2016 04 05 2016 07 02 Background: Myelodysplastic syndromes (MDSs) include a diverse group of clonal bone marrow disorders characterized by ineffective hematopoiesis and pancytopenia.It was found that down regulation of APAF1, a putative tumor suppressor gene (TSG),leads to resistance to chemotherapy and disease development in some cancers. In this study, we investigated the relation of APAF1 methylation status with its expression and clinicopathological factors in myelodysplastic syndrome (MDS) patients. Materials and Methods: Methylation Sensitive-High Resolution Melting Curve Analysis (MS-HRM) was employed in studying the methylation of CpG islands in the APAF1promoter region in MDS. Gene expression was analyzed by using real time RT-PCR. Results: 42.6% of patient samples were methylated in promoter region of APAF1 analyzed, while methylation of the genewas not seen in controls (P<0.05). Methylation of APAF1 was significantly associated with the suppression of its mRNA expression (P=0.00). The methylation status of APAF1in advanced-stage MDS patients (80%) was significantly higher than that of the early-stage MDS patients (28.2%) (P=0.001). The difference in frequency of hypermethylated APAF1 gene was significant between good (37.5%) and poor (85.71%) cytogenetic risk groups (P=0.043). In addition, a higher frequency of APAF1 hypermethylation was observed in higher-risk MDS group (69.2%) compared to lower-risk MDS group (34.14%) (P=0.026). Conclusion: Our study indicated that APAF1hypermethylation in MDS was associated to high-risk disease classified according to the IPSS, WHO and cytogenetic risk. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/590 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/590/548