Characterization of aflatoxin BI (AFB) in human liver cancer.

The occurrence of aflatoxin BI in human liver cancers was evidenced by thin layer chromatography followed by spectrophotometry of the chloroformic extract of tissue samples. Microscopic slides obtained from the same samples were also examined by direct fluorescence microscopy. In five cases, the chemical identification of aflatoxin BI was associated with the demonstration of a strong blue fluorescence of the tumor cells. In seven other samples, a slight blue fluorescence similar to that of AFB was observed, but the toxin was not detected by the chemical assay. In two cases, negative results were registered by both methods. The occurrence of AFB-macromolecules complexes not extractible by organic solvents and differences in the sensitivities of the two methods may explain the observed discrepancies.