While scientists have made significant progress in finding and combating the perpetrators of cancer growth, they've had less success in nailing down the proteins that facilitate the spread, or metastasis, of cancer.
Scientists working with mice have now demonstrated that four proteins appear to work in concert to both grow and spread tumor cells. The proteins had turned up previously in metastatic tumors.
The rogues' gallery includes an inflammatory enzyme called cyclooxygenase 2 (COX2), a protein known as epiregulin that's involved in cell growth, and two enzymes that have been implicated in the growth of new blood vessels that nourish tumors.
To test the proteins' roles, the researchers implanted metastatic human–breast cancer cells into healthy breast tissue in mice. The team had genetically engineered the cells going into some animals so that the tumors would fail to produce some or all of the proteins.