Cancer promoting potential of different strains of <i>Fusarium moniliforme</i> in a short-term cancer initiation/promotion assay

A short-term cancer initiation/promotion bioassay was established to screen 10 toxic strains of Fusarium moniliforme for their cancer promoting activity in rats. The assay consisted of a four week 'promoting' treatment, effected by incorporating culture material (5%) of each strain into the diet, commencing one week after an initiation treatment with diethylnitrosamine (DEN, 200 mg/kg). The appearance of gamma-glutamyltranspeptidase-positive (GGT+) foci was used as an indication of promoting activity. Three out of 10 strains of F. moniliforme obtained from corn from a high risk area for esophageal cancer in Transkei, southern Africa, had significant cancer promoting activity. A highly significant correlation was found between toxicity expressed as reduction in body weight gain and cancer promoting activity. This finding suggests that the compounds responsible for the hepatotoxicity and hepatocarcinogenicity of F. moniliforme could be identical.