The notably down-regulated by polyploidy tumour suppressors belong to DNA damage response: ATR, (2nd phylostratum), ATR (2nd), CHEK2 (2nd), CHEK1 (3rd), TP53 (5th)—however, its protein inhibitor MDM2 (seen in the column for oncogenes) is also inhibited; apoptosis executor Fas, prominent tumour suppressor PTEN (2nd) and the E-cadherin-associated gene CDH1 (8th phylostratum). The gene discussed is CHEK1; the disease is neoplasm.