Molecularly Targeted Therapy

What is molecularly targeted therapy?

Cancer cells each carry specialized proteins or molecules that signal for the growth and division of the cells. Molecularly targeted agents are designed to block these specific molecules and prevent the messages telling the cell to grow or divide from being transmitted. This inhibits proliferation and replication of the cancer cells, ultimately resulting in their death. In most cases, each molecularly targeted agent is effective against a single protein or molecule. Specialized testing of the cancer cells helps physicians determine whether a particular cancer is likely to respond to the targeted agent based on the presence or absence of the target protein in or on the cells. Molecularly targeted agents can be used alone or in combination with cytotoxic chemotherapies.

What are the benefits of molecularly targeted therapy?

Unlike cytotoxic chemotherapy agents which are indiscriminate and kill all rapidly dividing cells including some healthy cells, molecularly targeted agents selectively kill only those cells carrying the target protein. Consequently, they effectively treat the cancer with significantly fewer side effects.

Why aren’t all cancers treated with molecularly targeted therapy?

Molecularly targeted therapies are relatively new in cancer treatment, and not all cancers carry a protein that is the target of the currently available drugs. Sophisticated testing of each patient’s cancer cells help the physician determine whether molecularly targeted therapy is an option for a particular patient.