Opium and oesophageal cancer in Iran.
D000368:Aged; D002273:Carcinogens; D004938:Esophageal Neoplasms / Q000139:chemically induced / Q000209:etiology*; D006801:Humans; D007492:Iran; D008875:Middle Aged; D009892:Opium / Q000633:toxicity*; D019966:Substance-Related Disorders
D002273:Carcinogens; D009892:Opium