To establish if PHA-767491 could also inhibit CDK2 and reduce E2F1-3-mediated transcription in three RB+ cancer cell lines PC3 [40], SW480 [41] and SW620 [42] cells were treated with either CDK inhibitors (CVT313 and roscovitine) or DDK inhibitors (XL-413 and PHA-767491) (Figure 5A–C). This evidence concerns the gene RB1 and cancer.