Obtaining a genetic picture of how a tumor will react to the many treatment techniques available could help doctors prescribe therapies customized for individual cancer patients' needs, suggests a Purdue University research team. Their research appears in the Journal of Biochemistry.

A group of scientists including Jian-Jian Li has found a trio of proteins often present in cancer cells that protect the tumor from destruction by radiotherapy. Because no single protein in the group is responsible for keeping the cancer alive, Li said that the key to a successful assault could rest in a deeper understanding of the relationship among these protein molecules - an understanding that could be made available through genetic testing.

In the case of breast cancer cells, the proteins in question are ERK, NF-kappa B and GADD45 beta.

"We have discovered that breast cancer cells defend themselves on the molecular level against radiation, and this response could be reducing the effectiveness of modern medicine's fight against cancer," said Li, who is an associate professor of health sciences in Purdue's School of Health Sciences. "Because these three proteins interact in ways peculiar to each tumor, it might help doctors to first obtain the 'genetic fingerprint' of cancerous tissue in order to find out which treatment method will be most effective."

Li's group found that it was not just one of these proteins that was fighting hard to save the cells - it was all three. After subjecting breast cancer cells in the lab to the stress of ionizing radiation, the group found that the proteins all are co-activated in a pattern of mutual dependence, coordinating among themselves to increase cell survival rate.

"The essence of our discovery can expressed rather simply," Li said. "Genes in the body do not operate in isolation, but as a team. This is the sort of lesson we will probably learn again and again as the recently decoded human genome reveals more of its secrets."

Indeed, it could be in the genome that a solution to the dilemma will be found, Li said.

"If we can test cancer cells not for just three proteins but for thousands, the 'genetic fingerprint' such a test would provide might help us to devise better therapies to kill tumors," he said. "Knowing in general that proteins A, B and C are defending the cell may allow us to administer drugs that block them, which could allow us to irradiate the now-defenseless cancer with lower radiation levels. This would be simultaneously more effective against the cancer and less harmful to the patient in general."

SOURCES:
Journal of Biochemistry, April 2005
Purdue University (http://www.purdue.edu)