Question

Gleevec was one of the first targeted therapy drugs, and CML (chronic myelogenous leukemia) was the first disease treated with Gleevec.

i) Explain the benefits of targeted therapies over chemotherapy.

ii) Gleevec targets a hybrid protein in CML patients. Describe what causes this hybrid protein to form and what the protein does that results in cancer.

Answer 1

Targeted therapy (TT) has several benefits over chemotherapy which are represented here.

1. During the treatment of cancer or any related diseases, only the diseased cells should be attacked and killed, without harming the normal body cell. This is achieved by the TT. Chemotherapy only stops the cell doubling, not very specific.  

2. TT therapy agents or drugs can be given orally. Chemotherapy drugs are mostly intravenous, some oral agents.

Chronic myelogenous leukemia is a type of rare blood-cell cancer. In this case, the chromosome mutation occurs spontaneously. This happens with a consistent chromosomal translocation that results in sequences from the c-abl locus on chromosome 9 being fused to sequences in a breakpoint cluster region (bcr) on chromosome 22. The resulting protein gene (BCR-ABL) produces an altered protein.  This fusion protein with tyrosine kinase activity forms, which activates signal transduction pathways, leading to uncontrolled cell growth.