Aggressive cancer therapy target ID'd

DALLAS, Dec. 2 (UPI) -- U.S. scientists say they've found a protein that normally suppresses the growth of cancer can also cause aggressive cancer growth after prolonged exposure.

The University of Texas Southwestern Medical Center researchers said the protein -- transforming growth factor beta1 -- can cause cancer cells to become even more aggressive and likely to spread.

The mechanism for the reversal is unknown, but the researchers and their colleagues at the Indiana University of Medicine -- led by co-senior collaborator Dr. Lindsey Mayo -- suspect cancerous cells activate a defense mechanism in response to the lethal protein. That mechanism turns on a cascade of cancer-promoting genes.

The study's other co-senior author, Dr. David Boothman of UT Southwestern's Simmons Comprehensive Cancer Center, said clinicians might be able to exploit the rebound for better treatments.

"These genetic changes would start prior to metastases, so if we detect them early, we might be able to tailor treatment in anticipation of a more aggressive cancer," Boothman said.

The study, conducted on cells from mice and in samples from women with metastatic breast cancer, is available online and is to appear in the January issue of The Journal of Clinical Investigation.