This mathematical model describes the response of cytotoxic T lymphocytes to the growth of an immunogenic tumor, with the inclusion on a number of in vivo phenomena, such as the immunostimulation of tumor growth, evasion of immune function by the tumor, and the formation of a tumor "dormant state". Specifically, this model is used to describe the kinetics of growth and regression of the B-cell lymphoma BCL1 in the spleen of mice.