CHEK1 and lymphoma: Nevertheless, these results are consistent with studies using the CHK1 inhibitor PF-0477736 in a variety of Eμ-Myc driven transgenic murine lymphoma cell lines [18] and are directly comparable with antitumor studies using UCN01 (5mg/kg × 9 days), a non-selective CHK1 inhibitor in the same model [45].