Morphine does no promote esophageal carcinogenesis in rats exposed to diethylnitrosamine.

Background: The high incidence of esophageal cancer in the north of Iran has been associated to the consumption of opium and exposure to nitrosamines. Diethylnitrosamine has an established potential of producing experimental cancer in the esophagus and liver.

Aim: To evaluate by histopathology the effect of oral administration of morphine and diethylnitrosamine during 23 weeks on the hepatic and esophageal carcinogenesis on 176 rats.