Histochemical determination of copper, zinc, and iron in some benign and malignant tissues

Histochemical tests for copper, iron, and zinc revealed their presence in the stratum germinativum of normal skin and skin from which an early melanoma and basal cell and squamous cell carcinomas originated. However, only copper was seen in invasive cells of basal and squamous cell carcinomas originating from skin. The normal oral mucous membrane was free of copper, iron, and zinc, but cells of invasive squamous carcinoma originating from the oral mucous membrane contained copper. The fluorescent brightening agent, applied as a counterstain, aided in the location of the specimen.