Core HT module correlates with MYC-driven tumor growth in transgenic FVB/N mouse. Gene expression analysis of MYC and expression of ESC1 module in tumor cells from FVB/N mice with conditional overexpression of human MYC that were treated with different doses of doxycycline to down-regulate MYC. At 0.04 to 0.05 ng/mL doxycycline, the level of MYC has dropped below the threshold required for tumor maintenance. (A) The difference between the proportion of tumor cells undergoing growth versus apoptosis shifts in favor of the latter at a specific MYC level (threshold) required to maintain a tumor phenotype. (B) Mean expression of genes in the core FL transformation module, as determined from microarray analysis of mouse tumors at each level of doxycycline.