Heat may be key to cancer therapy
Researchers believe they have found out why so many men with testicular cancer survive against the odds.
Testicular cancer, such as that famously conquered by Tour de France winner Lance Armstrong, is often treatable even when it has spread.
Experts at Johns Hopkins University say the cells are super-sensitive to body heat making them more vulnerable.
And heat therapy may be used to combat other cancers they write in the Journal of the American Medical Association.
The testes are a few degrees cooler than the rest of the body as sperm are sensitive to heat and tend to die when they are placed at the normal body temperature of 37C.
"We tried to put our heads together about what we know about the differences between testicular and other cancers"
Professor Robert Getzenberg
Professor Robert Getzenberg and colleagues at Johns Hopkins Medical School say several pieces of evidence suggest that testicular cancer cells may also have this sensitivity to heat, making them more amenable to treatment, a phenomenon they term the 'Lance Armstrong effect'.
So, 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.
Studies in men who have a condition in which the testes do not descend and remain in the body show that the nuclear matrix, 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.
"We tried to put our heads together about what we know about the differences between testicular and other cancers. There is an amazing difference in treatment success and we wanted to come up with a simple idea that has a biological basis."
Professor Getzenberg said 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.
"Some groups are doing localised heating of tumours but the real advance would be to move this into people with systemic disease. These are not big golf ball size tumours they're small tumours that you can't really see."
"We need to think how we can target these cancer cells anywhere in the body."
Professor Getzenberg is using nanotechnology to target iron particles directly to cancer cells.
These 'nanoparticles' can be developed to be attracted to specific markers present on the surface of cancer cells.
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.
The team are currently assessing this technique for treating prostate cancer in animal models.
"These nanoparticles exist now and can be used in the body. The advantages are you don't have to put them in every cell as long as you are getting a warming environment," he said.
"We are also working on study on bladder cancer looking at putting a warm solution in the bladder, using a more localised approach."
Ed Yong, cancer information officer at Cancer Research UK, said: "If cancer cells can be shown to be susceptible to higher temperatures, heat therapy may well become an option for treating cancer patients.
"To be effective, the heat must be targeted to cancer cells while leaving healthy cells unharmed. Nanoparticles can provide a way of doing this.
"Nanotechnology is a very exciting new field of science and it is set to play an increasing role in detecting and treating cancers."
Story from BBC NEWS:
Published: 2006/07/25 23:07:24 GMT
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