TP53 and osteosarcoma: To explore the impact of p53 DNA binding cooperativity in a broader context, we compared our data obtained from Saos-2 osteosarcoma cells to p53 ChIP-seq data obtained in the breast cancer cell line MCF7 treated with 5-fluorouracil (5FU) or MDM2 inhibitors (nutlin-3a, RITA) [32] and the osteosarcoma cell line U2OS treated with actinomycin D or etoposide [31] (Fig. 4).