Experiments have shown that there is an increase in ultrasound backscatter from cells during cell death. Since cell scattering depends on the mechanical property variations, one step towards a better understanding of the phenomenon involves measuring the cells' viscoelastic properties. Two promising techniques used for such studies are particle tracking microrheology (1P) and two-point microrheology (2P). The main aim of this work is to develop and test the ability of both to measure changes in viscous and elastic moduli of breast cancer cells during chemotherapeutic treatments. First, the viscosities of glycerol-water mixtures measured using microrheology were found to be within 5% of rheometer values. The viscous and elastic moduli of 4% and 6% poly(ethylene oxide) solutions were successfully measured at 30°C and 37°C. For MCF-7 cells, a 10-fold increase in the elastic modulus was observed using 1P, without a corresponding increase in the viscous modulus. Thus, it was shown that MCF-7 cells undergo an increase in stiffness during apoptosis.