In addition, over-expression of a Lys-39 acetylation-defective C/EBPβ mutant protects against the LLC-induced muscle catabolism both in vitro and in vivo without affecting the Thr-188 phosphorylation status of C/EBPβ, indicating that p300-mediated acetylation of C/EBPβ plays a prominent role in the activation of this transcription factor in the cancer milieu. This evidence concerns the gene CEBPB and cancer.