Abstract: Methodologies and technologies for potentiating antibody-based cancer treatments by increasing complement-mediated cell cytotoxicity are disclosed. Further provided are methodologies and technologies for overcoming ineffective treatments correlated with and/or caused by sub-lytic levels of complement-activating monoclonal antibodies (“mAb”) against cancer antigens or cancer antigens with low tumor cell density. While detectable levels of passively administered or vaccine-induced mAb against some antigens are able to delay or prevent tumor growth, low levels of mAb induce sublytic levels of complement activation and accelerate tumor growth. This complement-mediated accelerated tumor growth initiated by low mAb levels results in activation of the PI3K/AKT survival pathway. Methodologies and technologies relating to administration of PI3K inhibitors to overcome low dose mAb-initiated, complement-mediated PI3K activation and accelerated tumor growth are disclosed.