PIWIL1 and infection: Compared to Caco-2 cells infected by Ad-RFP or Ad-Hiwi and without DAC treatment, there was a difference when DAC was more than 0.8 mM in HT-29 cells infected by Ad-RFP and when DAC was more than 0.2 mM in HT-29 cells after the infection with Ad-Hiwi (Figures 5(c) and 5(d)).