Treating cancer with surgery, chemotherapy or radiation may sometimes cause tumors to spread, researchers say.

Tests in mice show that using the chemotherapy drug doxorubicin or radiation both raised levels of TGF-beta, which in turn helped breast cancer tumors spread to the lung.

But using an antibody to block TGF-beta stopped the process, Dr. Carlos Arteaga and colleagues at Vanderbilt University in Tennessee have reported.

"We'll be looking to see in what proportion of patients the serum and tumor TGF-beta goes up, and whether the increase correlates with the inability of the therapy to eliminate the cancer in the breast," Arteaga said.

Higher levels of TGF-beta after treatment may be a way to predict which patients are likely to have their cancer come back after treatment, Arteaga added.

TGF-beta, however, is not the only element that is having this effect. Many other compounds, including some immune system signaling chemicals, are also associated with tumor spread and growth.

Researchers are also testing drugs that interfere with TGF-beta to see if they improve chances of survival.


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