CDK2 and retinoblastoma: In the Y79 retinoblastoma cell line, the mRNA levels of cdc25A, CDK2 and p21 were significantly lower in the PAX6 inhibition study group than in negative GFP-control group (cdc25A, 0.36±0.07 vs. 1.00±0.00; t=15.91; P<0.01, n=3; CDK2, 0.28±0.03 vs. 1.00±0.00; t=46.77; P<0.01, n=3; p21, 0.37±0.08 vs. 1.00±0.00; t=14.37; P<0.01, n=3) (Fig. 6B).