With the description of tumours in the oxyntic mucosa in rodents after long-term dosing with the first proton pump inhibitor (PPI) omeprazole [7], and the insurmountable histamine-2 (H-2) antagonist loxtidine [8], there has been concern that long-term inhibition of gastric acid secretion could also promote cancer in humans. This evidence concerns the gene ATP4A and neoplasm.