LONDON, Dec. 10 (UPI) -- A British study suggests the spread, or metastasis, of breast cancer cells into the bloodstream of mice is governed by a growth factor.
Erik Sahai of Cancer Research UK and colleagues said they have discovered the metastasis of individual breast cancer cells is controlled by transforming growth factor beta, or TGFb -- the same growth factor that has previously been shown to regulate normal cell growth and movement.
"The results helped us to find the set of genes that are behind the spread of breast cancer, Sahai said. The researchers discovered single breast cancer cells leave the primary tumor and enter the bloodstream when TGFb turns on messenger genes in the cancer cells, and later turns them off.
They also found that when TGFb is inactive, clumps of breast cancer cells leave the primary tumor and enter the lymphatic system rather than the bloodstream. They said the widespread metastasis of individual cancer cells throughout the body is more life-threatening than the more localized spread of groups of cells.
The study was presented this week in San Diego during the annual meeting of the American Society for Cell Biology and also appears in the journal Nature Cell Biology.
