Numerical simulations of proliferating and non-proliferating cells in the absence and presence of HIA and CTA treatment. Simulations of the model show P versus t (bottom curve) and N versus t (top curve). A. HIA and chemotherapy treatment are both absent (the control case). B. HIA is present and chemotherapy treatment in absent. It can be observed that HIA causes an increase in the level of P as compared with the control case. Due to the time dependent nature of HIA, the steady state value of P is the same as in the control case. C. HIA is absent and chemotherapy treatment is present. The presence of CTA causes a drastic decrease in the level of P as compared with the control case. The steady state value of P is below the initial value P(0) = 100 which is the desired result. D. HIA and chemotherapy treatment are both present. For an appropriate choice of the dosage of HIA administration, the minimum level of P can be kept close to that observed in the control case.