Active mutations of ras can be detected in more than 30% of human malignancies, which has drawn intensive attentions and efforts to understand the structures, biochemistry and biology of this onco-protein, and further to target it as new strategies for treating tumors harboring mutated ras. The notion of the therapeutic approaches is that in order to maintain and cope with a high metabolic rate of a cancer cell, oncoproteins need the supports from parallel to or distal of signaling pathways. Here, PROS1 is linked to cancer.