Metastases are the cause of 90% of human cancer deaths. Cancer in _situ_ can usually be effectively removed by surgery. Once cancer cells disseminate from the original site and start to circulate in blood, lymph, or other body fluids, the disease becomes almost incurable. Here we show that cancer cells in a non-adherent, 3-dimentional growth pattern are highly drug resistant compared to their adherent counterparts that grow in monolayer, attaching to the wall of tissue culture plates. The non-adherent cancer cells retain the adhering potential and can attach to an appropriate surface to reacquire adherent phenotype. Once the non-adherent cancer cells become attached, they regain drug response, similar to the original adherent cells. A significant increase... |