The mice study linked below appears to confirm suspicions that chemo & radiation may induce TGF-beta as a side effect which has been found to be one of the factors promoting metastases in metastatic BC.
The good news is that, in mice, inhibition of TGF-beta prevented new metastases. More studies of TGF-beta are underway to find uses as monitoring or predictive marker.
http://www.eurekalert.org/pub_releas...-tgf040207.php
Treatment-induced growth factor causes cancer progression