Residual tumor cells are a barrier to targeted cancer th...( was no longer dependent upon MYC for g...),Health

With these experiments, Chodosh and colleagues demonstrated that small numbers of breast cancer cells that remain following targeted therapy provide a means for cancers to escape and eventually recur. When tumors shrink in response to therapy, they leave residual cells that ultimately give rise to recurrences. Furthermore, if the targeted oncogene becomes reactivated in those cells, they grow into full-blown tumors very quickly. "Any way you look at it, when physicians apply a selective pressure to a tumor by blocking an oncogenic pathway, cells escape," says Chodosh. "They find a back door and progress to a more aggressive state that becomes independent of that pathway."

Chodosh concludes that the type of genetically engineered mouse models used in these MYC studies yield results that are very similar to what is observed in patients and that molecular therapies will likely need to be applied chronically to prevent the regrowth of residual tumor cells that remain after therapy. He further emphasizes that molecularly targeted therapies will need to be combined with agents that target secondary pathways of tumor escape in order to achieve lasting cures.

'"/>

Contact: Karen Kreeger
karen.kreeger@uphs.upenn.edu
215-349-5658
University of Pennsylvania School of Medicine
4-Jan-2005