The role of Smad4 as a tumour suppressor was initially identified in pancreatic cancer as being absent in pancreatic cancer 4 (DPC4)4,22, 23, 24 and since then loss of Smad4 has been identified in a key driver in skin cancer,25 head and neck cancer,26 and other cancers.16, 19. The gene discussed is SMAD4; the disease is cancer.