PROS1 and cancer: Its molecular mechanisms underlying cancer cell apoptosis may include but are not limited to provoking cellular ROS stress, suppressing cellular antioxidants (catalase, SOD1, and TRX) and ROS-resistant regulator (NRF-2), upregulating the tumor suppressor (P53) and pro-apoptotic protein (BAX) but downregulating pro-survival proteins (BCL-2 and MCL-1) and deactivating survival signals (AKT and ERK), and increasing apoptotic enzyme cleavages (caspase 3/7 and PARP).