t(9;22)(q34;q11) translocation is commonly associated with: September 2007

Ans. C: CML All CML have a t(9;22), at least at the molecular level; but not all t(9;22) are found in CML. Chronic myelogenous leukemia (CML) is characterized by the Philadelphia chromosome, resulting from a balanced translocation between the long arms of chromosome 9 and 22, the t(9;22)(q34;q11). In the formation of the Philadelphia chromosome, the region of the c-ABL oncogene is transposed from 9q34 to the region of the BCR gene on chromosome 22 to form a fusion gene BCR-ABL, which encodes a fusion protein with constitutive tyrosine kinase activity. In almost all the cases with variant Philadelphia chromosome, the BCR-ABL rearrangement can be detected by molecular methods or by fluorescence in situ hybridization (FISH).