As late passage HCT116 tetraploid clones did not express the high levels of cyclin D1 and p21 observed in the early clones (Figure 1E and supplementary Figure S1d, available at Annals of Oncology online), it is possible that tumours which have undergone genome-doubling during their evolutionary history more closely resemble these later passage clones, and that high cyclin D1 expression is transient and dispensable with time. This evidence concerns the gene CDKN1A and neoplasm.