Chronic Myelogenous Leukemia (CML) Results from a Translocation Between Human

Multiple Choice

Chronic myelogenous leukemia (CML) results from a translocation between human chromosomes 9 and 22. The resulting chromosome 22 is significantly shorter than usual, and it is known as a Philadelphia (Ph') chromosome. The junction at the site of the translocation causes overexpression of a receptor tyrosine kinase. A new drug (Gleevec or imatinib) has been found to inhibit the disease if the patient is treated early. Which of the following would be a reasonably efficient technique for confirming the diagnosis of CML?

A) searching for the number of telomeric sequences on chromosome 22
B) looking for a Ph' chromosome in a peripheral blood smear
C) enzyme assay for receptor tyrosine kinase activity
D) fluorescent labeling to determine the chromosomal location of all chromosome 22 fragments
E) identification of the disease phenotype in review of the patient's records