Chromatin immunoprecipitation (ChIP) followed by microarray hybridization (on-chip) is a technique well suited for a comprehensive analysis of transcription factor binding sites, histone modification patterns, and nucleosome occupancy. It can be restricted to a subset of genes or regions but also expanded up to a genome-wide range yielding insight into the functional elements of gene regulatory networks. Mutant p53 proteins have lost their capacity to bind to its cognate binding sites, but it is well established that it has retained the ability to bind indirectly to DNA via other transcription factors and therefore change the expression of several target genes. The identification of those transcription factors and binding regions sheds light on how mutant p53 is able to exert oncogenic functions.