In a range of ecMYC (c-MYC) cancer cell lines treatment with hydroxyurea, which inhibits ribonucleotide reductase, resulted in a marked reduction in c-MYC copy number that was not observed in a cell line harbouring c-MYC on an HSR (Colo320HSR) (Von Hoff et al. 1992). Here, MYC is linked to cancer.