Figure 2. Algorithm flowchart.

Refer to Materials and Methods and Text S1 for equations. Using the cellular-scale data, we measured values for proliferation and apoptosis for both drug-sensitive and drug-resistant tumors and calculated corresponding values for the model mitosis and apoptosis parameters λ _M and λ _A. We solved Eq. (2) for the local levels of cell substrates n at each time step of simulation of tumor growth. The parameters were input into Eq. (3) to numerically calculate the source mass terms S_i, which were then used in Eq. (1) to compute the volume fractions of viable ρ _V and ρ _D dead tissue. These fractions were used in Eq. (4) to obtain the tumor tissue growth velocity.