Reevaluation of the number of cells involved in the neutron induction of mammary neoplasms

Abstract

The shape of the curve relating carcinogen dose to the number of animals developing neoplasms is reexamined; a family of curves relating expected tumor incidence to carcinogen dose, if tumors arose from one cell or two or more interacting cells, is calculated; and how closely these curves correspond to reported radiation dose inrelation to mammary tumor incidence is tested. The results are in conflict with the conclusion of Rossi and Kellerer that the induction of mammary tumors in Sprague-Dawley rats is dependent on the action of neutron radiation on more than one cell. Indeed, there appears to be no reason to reject the simplest hypothesis that one transformed cell is sufficient to produce a mammary tumor.