Heat treatment may zap cancer cells

Jul 26 2006

Scientists believe they have discovered a clue as to why so many men with testicular cancer survive against the odds.

Testicular cancer, is often treatable even when it has spread and the experts say a simple factor such as heat sensitivity may make testicular cancer cells more susceptible to standard treatments and die off more readily.

A team of scientists at Johns Hopkins Medical School have linked scientific evidence spanning more than 30 years which suggests testicular cancer cells are super-sensitive to body heat and that makes them more vulnerable.

They say patients such as seven-time Tour de France winner Lance Armstrong who was diagnosed with testicular cancer at 25, survive far better than patients with other advanced cancers and heat may offer a strategy against other malignancies as well.

Robert Getzenberg, Ph.D., professor and director of urology research at Johns Hopkins says an understanding of how heat may naturally help kill testicular cancer cells, may enable it to be used in other solid tumors.

It appears that the testes are a few degrees cooler than the rest of the body as sperm are sensitive to heat and they tend to die when they are placed at the normal body temperature of 37C.

Getzenberg and colleagues say evidence suggests that testicular cancer cells may also have this sensitivity to heat, making them more amenable to treatment, a phenomenon they label as the 'Lance Armstrong effect'.

When the cells spread to other areas of the body, they may be weakened by higher temperatures, becoming more susceptible to chemotherapy or radiotherapy than other types of cancer.

Other studies in men with a condition in which the testes do not descend and remain in the body show that the nuclear matrix which is the protein scaffolding in the control centre of the cell, becomes 'wrecked' and is heat sensitive.

Professor Getzenberg and his team are now experimenting with different methods of weakening the nuclear matrix in cancer cells by heat.

Getzenberg says heat, or hyperthermia, is a very old form of cancer therapy but in order to make it a successful it needs to be targeted specifically at cancer cells.

He and his team are now using nanotechnology to target iron particles directly to cancer cells in animal models.

Once attached to the cancer cells they can be heated using an external magnetic field, weakening the cells and hopefully making them more susceptible to chemotherapy or radiation.

Nanoparticles can provide a way of targeting the heat at cancer cells while leaving healthy cells unharmed.

They are also working on a study of bladder cancer and are examining the effects of putting a warm solution in the bladder and using a more localised approach.

The scientists believe that if injected through the bloodstream, magnetic nanoparticles may be able to reach tumors throughout most of the body and as long as the nanoparticles penetrate most of the cells in the tumor, the temperature increase will spread to the entire mass.

The research is published in the Journal of the American Medical Association.