The College of Science in the Department of Mathematics discussed a master thesis titled NUMERICAL STUDY AND STABILITY OF DELAY DIFFERENTIAL EQUATIONS OF TUMOR GROWTH AND ITS PARAMETER ESTIMATION PROBLEM for postgraduate Ibrahim Makki Khalil. The thesis aims to consider a class of cancerous tumor cells with differential equations with a time delay that illustrates and represents the interactions of the tumor cells with effector cells including immune response of natural, dendritic and cytotoxic cells.