About ten years ago I was invited to initiate a long term cancer project at Barnard Hospital. It was decided to study development of cancer in the most favorable experimental conditions that could be found.
Epidermis was chosen as the tissue chiefly because it makes up the surface of the body and is easily accessible. But we had in mind also other advantages. It provides cells of a single type conveniently arranged in layers of increasing differentiation with a minimum of intercellular material and no blood vessels. Because of its avascularity and high degree of cellularity, chemical analyses relate more directly to the epidermal cells than do those of any other tissue.
Mice of a closely inbred strain were selected as the animals in order to reduce individual variability to a minimum.
Methylcholanthrene was selected as the carcinogen because substances of somewhat similar nature naturally occur in the body and