Zollinger-Ellison syndrome, prolonged cimetidine administration and nasopharyngeal carcinoma:--a coincidence?

A patient with Zollinger-Ellison syndrome who developed an undifferentiated nasopharyngeal carcinoma (NPC) after 3 years of daily treatment with a least 1.0 g cimetidine is described. The question is raised whether large doses of cimetidine, administered for long periods to patients perhaps already immunologically compromised, may change T-suppressor cell functions so as to enable proliferation of oncogenic viruses (e.g. EB virus) and the appearance of tumor. We feel that when the population at risk is small, even a solitary case should alert all concerned.