This generates an 80 kDa active protein kinase that translocates to the nucleus to regulate differentiation through STAT5 signalling (Lee et al, 2002; Rio et al, 2000), and nuclear localization of this soluble intracellular domain is associated with poor survival in breast cancer models (Junttila et al, 2005). The gene discussed is WEE1; the disease is breast carcinoma.