CHEK1 and cancer: ↓ Cancer cell proliferation, ↑ arrest in the G2/M phase, ↓ cell numbers in the G0/G1 phase, ↑ tetraploid cells, ↑ DNA damages, ↑ γ-histone 2AX (γH2AX), ↓ ataxia telangiectasia and Rad3-related (ATR), ↑ p-check point kinase1 (Chk1), ↑ p-ataxia-telangiectasia mutated (ATM), ↑ p-p53 (Ser15), ↓ vascular endothelial growth factor (VEGF), ↓ VEGF-receptor 2 (VEGFR2), ↓ hypoxia-inducible factor-1 alpha (HIF-1α), ↓ HIF-1β, ↓ p-signal transducer and activator of transcription 3 (STAT3, pY705), ↑ ROS