eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2015-04-28 6 2 293 300 10.13005/bpj/417 2729 article Janar J. Yermekbayeva 1 L.N.Gumilyov Eurasian National University, Faculty of Physics and Technical Sciences, Department System Analyses and Control, 2 Mirzoyan Street, Astana - 010 008, Kazakhstan. In this paper, we present a new mathematical analysis that models the growth and control of tumors in living tissue. In these models, we use the D-factor, a fold form from catastrophe theory, to impose control on tumor growth. By adjusting parameters, the models exhibit stationary states at which the immune system is stabilized and the number of tumor cells is either driven to zero or remains constant. https://biomedpharmajournal.org/vol6no2/structurally-steady-control-of-tumor-cell-populations/ Regulation of immune system Control system Robust stability Lyapunov function Compensatory effect D-factor Structurally steady mappings Bifurcation values