PPP1R13L and breast cancer: Constitutive activation of RelA/p65 has been reported in breast cancer [33], so we compared the inhibitory effect of FL-iASPP, iASPP(295-828) and iASPP(92-828) on RelA/p65 transcriptional activity in the breast cancer cell line SK-Br-3, in which RelA/p65 is constitutively activated [34, 35].