Scientists
have engineered novel proteins that work like ‘guided missiles’ which seek out
cancer cells and deliver chemotherapy drugs to treat hard-to-reach tumours
without harming healthy cells. Although chemotherapy drugs do often effectively
kill cancer cells, they also damage other quickly dividing cells in the body,
causing side effects ranging from cosmetic, like hair loss, to disabling.
Sometimes,
the drugs dose needed to kill a tumour may be more than what a person’s body
can handle. This might happen if the tumour does not have much of a blood
supply and very little of the drugs, which is delivered through the
bloodstreams, can get in. A dose high enough to infiltrate the tumour could be
deadly to other cells in the body.
Some recently
approved therapies get around this problem using antibodies to deliver a drug directly
to tumours, by passing healthy cells and possibly overcoming some of the uglier
aspects of cancer chemotherapy. Although the two techniques are conceptually
similar, the specialized protein has the potential advantage of being able to
pass through the barrier that protects the brain, thereby being able to treat
brain tumours. It is also smaller than the antibody and might be able to reach
dense tumours with little blood supply.