Described herein are, inter alia, methods for decreasing the growth of a cancer cell, the method comprising delivering to a target cancer cell a growth-inhibitory amount of an atovaquone-related compound, wherein, prior to the delivery, an increased level of activation of the mTOR pathway in the cancer compared to a control level of activation of the mTOR pathway has been found. Also provided are methods for determining the susceptibility of cancer to treatment with an atovaquone-related compound and for assessing the success of therapy with such a compound.
