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December 16, 1968


JAMA. 1968;206(12):2735-2736. doi:10.1001/jama.1968.03150120069022

Normal mammalian epidermal cells produce a tissue-specific substance (chalone or colyone), which inhibits epidermal mitosis and maintains the balance between cell production and cell loss in the epidermis. Bullough and Laurence1 postulate that this regulatory mechanism of new cell growth must be disturbed in tumors and in tissues with malignant changes. To examine this hypothesis, the chalone production in the presence of a growing tumor was investigated.

The cells of epidermal tumor in experimental animals contained at least some epidermal chalone; however, smaller amounts of chalone existed in the tumor tissue than in the normal tissue. This could be explained by the fact that the epidermal chalone escapes from the tumor into the surrounding tissue or the production of chalone by the tumor cells is decreased. Normal epidermal cells, treated with the tumor-derived epidermal chalone, responded by mitotic inhibition only when adrenalin and hydrocortisone were added. Other experiments in