Targeted Cancer Therapies

Traditional cancer therapies, such as chemotherapy and radiotherapy, are not highly selective in targeting cancer cells and, therefore, have various side effects on normal cells of the body as well. 

In contrast, targeted cancer therapies use drugs designed to target specific molecular structures that are present only in the cancer cells, and are absent in normal cells.

For example, healthy cells have two separate genes, BCR and ABL1. In chronic myeloid leukemia, chromosomal translocation fuses a part of the BCR gene with the ABL1 gene, leading to the synthesis of fusion protein BCR/ABL1.

This abnormal fusion protein drives uncontrolled cell proliferation and results in an excessive number of white blood cells in the bloodstream.

Imatinib mesylate is a small molecule kinase inhibitor that can specifically target the BCR/ABL1 fusion protein, preventing its activity and the downstream signaling pathways that control cell proliferation.

The drug also inhibits the ABL1 protein in the healthy cells, but additional redundant tyrosine kinases in such cells cover up for the loss of function of the ABL protein.

Imatinib mesylate is an example of a successful targeted molecular therapy again