MYC threshold required to maintain tumor phenotype

We demonstrate that there is a level of MYC expression that is required for maintaining a tumor phenotype and at this threshold there is a switch from a state of cellular proliferation to a state of proliferative arrest and apoptosis. We analyzed changes in gene expression by oligonucleotide microarray analysis and quantitative PCR and found significant changes (FDR=5%) in 2348 down regulated genes and 1573 upregulated genes. Critical changes in gene expression that occurred at or near the threshold level of MYC expression includes genes that have been implicated in G1/S, G2/M cell cycle checkpoint pathways and death receptor/apoptosis signaling. Keywords: Dose response - MYC inactivation by doxycycline treatment 11 samples, replicates not included