PLAU and neoplasm: uPA concentration is modeled to decay from the center of the tumor (xc, yc, zc), asC(x,y,z)=(1+(x−xc)2σx2+(y−yc)2σy2+(z−zc)2σz2)−p,where (σx, σy, σz) represents the distance from the tumor that the substance is halved in each x, y, and z direction, and p represents how gradually the substance decay.