We demonstrated that PXR expression reduced p53 transactivation and the expression of its downstream target genes involved in cell cycle arrest and apoptosis.2 Similar to previous findings from our laboratory,12 PXR expression significantly decreased p53 recruitment to the promoter regions of various p53 target genes, including CDKN1A and MDM2. 2 We also showed that the elevated PXR expression decreased doxorubicin- and nutlin-3a-mediated toxicity, and promoted malignant transformation in colon cancer cells. This evidence concerns the gene TP53 and malignant colon neoplasm.