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CDKN2B methylation status and isolated chromosome 7 abnormalities predict responses to treatment with 5-azacytidine.

Authors: Raj, K  John, A  Ho, A  Chronis, C  Khan, S  Samuel, J  Pomplun, S  Thomas, NS  Mufti, GJ 
Citation: Raj K, etal., Leukemia. 2007 Sep;21(9):1937-44. Epub 2007 Jul 5.
Pubmed: (View Article at PubMed) PMID:17611569
DOI: Full-text: DOI:10.1038/sj.leu.2404796

5-Azacytidine, a DNA methyl transferase inhibitor, is effective in patients with myelodysplastic syndromes (MDS). Whether responses to 5-Azacytidine are achieved by demethylation of key genes or by cytotoxicity is unclear. Of 34 patients with MDS or acute myeloid leukaemia (AML) treated with 5-Azacytidine, 7 achieved complete remissions (CR) (21%) and 6 achieved haematological improvement. All six had less than 5% bone marrow (BM) blasts at the time of haematological improvements (HI) (2 had pre-existing refractory anaemia (RA), 4 had refractory anaemia with excess blasts (RAEB)). A further patient with RAEB had blast reduction to less than 5% without HI. Five of the seven (71%) complete responders had chromosome 7 abnormalities. BM CR predicted longer overall survival (OS) (median 23 versus 9 months, P=0.015). Bisulphite genomic sequencing (BGS) of the CDKN2B (p15(INK4b)) promoter showed low level, heterogeneous pretreatment methylation (mean 12.2%) in 14/17 (82%) patients analysed. Lower baseline methylation occurred in responders (9.8% versus 16.2% in non-responders P=0.07). No response was seen in patients with >24% methylation, in whom p15(INK4b) mRNA was not expressed. 5-Azacytidine reduced CDKN2B methylation by mean 6.8% in 8/17 (47%) patients, but this did not correlate with response. At 75 mg/m(2), cell death (reduced BM cellularity (P=0.001) and increased apoptosis (P=0.02)) rather than demethylation of CDKN2B correlates with response. Patients with >24% methylation may benefit from alternative dosing or combination strategies.

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CRRD Object Information
CRRD ID: 11252169
Created: 2016-06-27
Species: All species
Last Modified: 2016-06-27
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.