As the PANX1 channel regulates ATP release to the external environment in mammalian cells (Silverman et al., 2008), the block to import upon PANX1 inhibition raises the possibility that this channel may be responsible for both release and uptake of ATP in mammalian cells and so play a vital role in nucleoside phosphate homeostasis in tissues and tumours. The gene discussed is PANX1; the disease is neoplasm.