TP53 and cancer: Interestingly, although knockdown of PHLDB3 had a minimal effect on p53 activation (Supplementary Fig. 5b), overexpression of FLAG-PHLDB3 did suppress p53 activity and desensitize p53 response to doxorubicin treatment in WI-38 cells (Supplementary Fig. 5a), indicating that relatively low level of PHLDB3 in normal cells is not sufficient to have dramatic impact on p53, while once overexpressed, consistent with the scenario often found in cancer cells (Fig. 3), PHLDB3 acts as a p53 negative regulator.