Philadelphia chromosome is seen in:
High-Yield Explanation
The Philadelphia chromosome, characteristic of CML and a subset of acute lymphoblastic leukemias, provides the prototypic example of an oncogene formed by fusion of two separate genes. In these cases, a reciprocal translocation between chromosomes 9 and 22 relocates a truncated poion of the proto-oncogene c-ABL (from chromosome 9) to the BCR (breakpoint cluster region) on chromosome 22. The hybrid fusion gene BCR-ABL encodes a chimeric protein that has constitutive tyrosine kinase activity. Ref: Robbins 8th edition Chapter 7.