Aberrant methylation of the major breakpoint cluster region in chronic myeloid leukemia

摘要: Isolated hypomethylated sites exist in the major breakpoint cluster region (M-bcr) where most Philadelphia chromosome (Ph) breakpoints are located. Twenty of 50 (40%) chronic myeloid leukemia (CML) patients were found to have aberrant hypermethylation these on rearranged M-bcr when compared with control marrows. The aberrancy correlated strongly location; 19 20 cases had located 5′ Sca I site, and 28 30 normal methylation 3′ site. Sequence analysis Ph failed find an M- bcr nucleotide position that delineated transition between abnormally normally methylated cases, indicating translocation a critical sequence was not responsible for abnormality. In 3 8 CML patients, cells without t(9;22) methylated, unrearranged M-bcrs. data indicate M-bcrs present site Ph- may also be methylated.