Chronic myeloid leukaemia (CML) is characterized cytogenetically by a t(9;22)(q34;ql1) reciprocal translocation which gives origin to a hybrid BCR-ABL gene, encoding a p2lO(BCR-ABL) fusion protein with elevated tyrosine kinase activity and transforming abilities. The t(9;22) was suggested to be associated with genomic imprinting of centromeric regions of chromosomes 9 and 22, but the genes directly affected by the translocation, ABL and BCR, were shown not to be imprinted. For most diagnostic and research purposes the BCR-ABL gene can be efficiently identified by reverse-transcription and polymerase chain reaction (RT/PCR) amplification of its fusion transcripts, which can be quantified by competitive PCR and similar assays for assessment of residual disease in the follow-up of therapy. In the great majority of CML patients the BCR-ABL transcripts exhibit a b2a2 and/or a b3a2 junction; in rare cases, the only detectable BCR-ABL transcripts have unusual junctions, such as b2a3, b3a3, e1a2 or e6a2. There is a recent suggestion that the BCR-ABL gene may not be always 'functional', since extremely low levels of BCR-ABL transcripts can be found in leucocytes from normal individuals and, conversely, it appears that no BCR-ABL transcription can be detected in a proportion of Ph-positive haematopoietic progenitors from some CML patients. The role, if any, of the reciprocal ABL-BCR hybrid gene in CML is unknown. Although its mRNA message is in frame, no ABL-BCR fusion protein has yet been identified in CML patients. The blast crisis of CML has been variably associated with abnormalities of proto-oncogenes, such as RAS and MYC, or of tumour suppressor genes, in particular RB, p53 and p16, or with the generation of chimeric transcription factors, as in the AML1-EVI1 gene fusion. It is likely, therefore, that multiple and alternative molecular defects, as opposed to a single universal mechanism, underlie the acute transformation of the disease.
Chronic myeloid leukaemia ( CML ) is characterized cytogenetically by a t(9;22)(q34;ql1 ) reciprocal translocation which gives origin to a hybrid BCR - ABL gene , encoding a p2lO(BCR - ABL ) fusion protein with elevated tyrosine kinase activity and transforming abilities . The t(9;22 ) was suggested to be associated with genomic imprinting of centromeric regions of chromosomes 9 and 22 , but the genes directly affected by the translocation , ABL and BCR , were shown not to be imprinted . For most diagnostic and research purposes the BCR - ABL gene can be efficiently identified by reverse - transcription and polymerase chain reaction ( RT / PCR ) amplification of its fusion transcripts , which can be quantified by competitive PCR and similar assays for assessment of residual disease in the follow - up of therapy . In the great majority of CML patients the BCR - ABL transcripts exhibit a b2a2 and/or a b3a2 junction ; in rare cases , the only detectable BCR - ABL transcripts have unusual junctions , such as b2a3 , b3a3 , e1a2 or e6a2 . There is a recent suggestion that the BCR - ABL gene may not be always ' functional ' , since extremely low levels of BCR - ABL transcripts can be found in leucocytes from normal individuals and , conversely , it appears that no BCR - ABL transcription can be detected in a proportion of Ph - positive haematopoietic progenitors from some CML patients . The role , if any , of the reciprocal ABL - BCR hybrid gene in CML is unknown . Although its mRNA message is in frame , no ABL - BCR fusion protein has yet been identified in CML patients . The blast crisis of CML has been variably associated with abnormalities of proto - oncogenes , such as RAS and MYC , or of tumour suppressor genes , in particular RB , p53 and p16 , or with the generation of chimeric transcription factors , as in the AML1-EVI1 gene fusion . It is likely , therefore , that multiple and alternative molecular defects , as opposed to a single universal mechanism , underlie the acute transformation of the disease .
Which gene fusion is the result of the "philadelphia translocation" or the "philadelphia chromosome" mutation?
Which gene fusion is the result of the " philadelphia translocation " or the " philadelphia chromosome " mutation ?
ABL/BCR fusion
The BCR/ABL gene fusion ABL/BCR fusion