Introduction

Molds are usually considered to be a hazard mainly in hot humid climates, where their presence is readily apparent. These regions are not the locations of the world where the incidence of esophageal cancer is especially high. The mold most likely to be implicated in esophageal cancer, however – Fusarium – is found growing most often under cooler conditions. It is therefore generally a field fungus rather than a storage fungus.

The ability to grow under cold conditions gives Fusaria an advantage over other molds, and surprisingly it flourishes on vegetation growing under snow. This led to the tragic events which made Fusarium notorious as a human hazard. In Russia, after the First World War, when labour was not available for harvesting the cereals in autumn, crops were left to overwinter in the fields under the snow. In the following spring when they were harvested and used for making bread, outbreaks of alimentary toxic aleukia were widespread. The disease was shown to be due to infection of the corn with Fusarium species (Joffe 1974, 1978), and among the symptoms, to be described in more detail later, were hemorrhagic necrotic lesions in the esophagus. It is regrettable that the survivors of these disasters were not followed up and examined for evidence of carcinogenicity of the mold. However, crude extracts of Fusarium isolated from the toxic grain associated with the disease caused hyperkeratosis and basal cell hyperplasia of the esophageal squamous epithelium when fed to rats.