EPO and neoplasm: This hypothesis appeared to be supported by the literature, as some investigators have reported that tumour samples and cell lines transcribe the EPOR gene at high levels, that 90–100% of primary human tumours overexpress EpoR protein, and that recombinant human Epo (rHuEpo) induced proliferative, survival and migration effects on tumour cell lines (reviewed by Osterborg et al, 2007; Sinclair et al, 2007).