By Calvin Palmer
A vaccine to protect against breast cancer could soon be offered to women. Clinical trials are expected to go ahead within the next two years.
The vaccine is being developed at the Cleveland Clinic’s Lerner Research Institute, in Ohio, and could eventually be offered to women before they reach their mid-40s, when the risk of breast cancer starts to rise steeply.
“We think it will provide substantial protection,” said immunologist Vincent Tuohy. “Our view is that breast cancer is a completely preventable disease.
“We truly believe that a preventive breast cancer vaccine will do to breast cancer what the polio vaccine has done to polio.”
Tuohy’s vaccine has proven effective in tests on laboratory animals. It makes the immune system attack a particular protein found in most breast cancer cells and the mammary tissues of breastfeeding women. As such, it would only be given to women who are not going to breastfeed in the future.
“The frequency of women who breastfeed in their early 40s and above is very low, so we are looking at vaccinating women against the disease from this stage of life onwards,” Tuohy said.
The vaccine is based on protein called alpha-lactalbumin that lurks in most breast cancer tumors.
In tests on mice bred to develop breast cancers by the age of 10 months, the drug was found to keep them free of tumors, the journal Nature Medicine reports.
The jab stimulates the immune system, priming it to destroy alpha-lactalbumin as it appears, and so stopping tumors from forming.
The drug also harnessed the power of the immune system to shrink pre-existing tumors by up to half, suggesting it could be used as a treatment as well as a vaccine.
Effective cancer vaccines have proved notoriously difficult to make, not least because tumor cells are strikingly similar to healthy tissues.
A poorly-designed cancer vaccine could easily turn the immune system against other parts of the body and cause more harm than good, while another problem is that many cancers weaken the immune system as they grow.
But as the protein targeted by the new drug is only found in healthy breasts when they are producing milk, the jab should specifically target diseased cells, leaving other tissue untouched.
Tuohy hopes to begin clinical trials of the vaccine on women next year but it will be at least 10 years before it is available on the market.