The clinician's dealings with cancer are, in general—and regrettably so—associated with what one may call advanced disease. The concepts of the earliest and smallest lesions are vague even among experts. I have been interested, perhaps impractically, in lesions that are clinically, at the time examined, of no apparent consequence. I shall present material concerned especially with these small and early lesions.
Cancer is a cellular disease. It begins in one or at the most in only a few cells.
That cancer is a cellular disease is made evident by a number of facts. All animals and perhaps plants are subject to cancer. Cancer has been observed in human beings, rats, mice, chickens, dogs, cats, horses, fruit flies and many other creatures. On apples mole-like lesions composed of irregular masses of cells, which differ from normal somatic cells in the inability of the scab fungus to grow on them, have been
SUTTON RL. EARLY EPIDERMAL NEOPLASIA: DESCRIPTION AND INTERPRETATIONTHE THEORY OF MUTATION IN THE ORIGIN OF CANCER. Arch Derm Syphilol. 1938;37(5):737–780. doi:10.1001/archderm.1938.01480110003001