CCK-8 assay was used for cell counting every 24 hours for Caco-2 or HT-29 cells after the infection with Ad-Hiwi or Ad-RFP, as shown in Figure 3(a); the proliferation rate of Caco-2 cells which were infected with Ad-Hiwi was significantly higher than cells which were infected with Ad-RFP (p < 0.01 for 24 or 48 hours postinoculation (H.P.I.)) and the promotion by Ad-Hiwi infection was also confirmed in HT-29 cells (Figure 3(b); p < 0.05 or p < 0.001 for 24, 48, or 72 H.P.I.). This evidence concerns the gene PIWIL1 and infection.