Differential fluorescence staining of normal and neoplastic tissues: Use of various serum proteins

APPROPRIATE circumstances a fluorescein-I globulin stain will distinguish between normal and neoplastic cells of experimentally induced and naturally occurring tumors;16.2O some of the features of this phenomenon have now been investigated in further detail.From the time, 3 decades ago, when the production of chemical carcinogens in pureform facilitated the study of their effects on tissues,)I 4-16 their mode of action has been the subject of special inquiry.In 1940, Graffis showed that 3,4benzpyrene became concentrated in the cells of the skin, that is, in the region that was subsequently to become neoplastic.Later this was found to apply to rat liver in animals fed 4-dimethylaminoazobenenzene DAB), the dye being firmly bound to the cell protein.22Subsequently the same phenomenon was observed in the skin with 1,2,5,6- dibenzanthracene.26A more extensive series of aromatic hydrocarbons (carcinogenic and noncarcinogenic) was investigated by Heidelberger and Moldenhauerlo who found a correlation between carcinogen binding and carcinogenicity.This feature has been observed with still other carcinogens and appears to be a general characteristic of these substances.Studies of the cytoplasmic proteins by differential centrifugation and electrophoresis show that the dye, when present, is in a part of the soluble proteins of the cytoplasm.The particular protein complex with which the dye is associated has a low electrophoretic mobility at an alkaline pH.Components with corresponding mobility are absent or greatly diminished from the corresponding neoplastic cell.These findings are in accordance with the suggestion that a basic protein complex with dye-binding properties is deleted from tumor cells.These observations have led to several hypotheses that emphasize this difference in con-