ABSTRACT
Cell proliferation, triggered either as part of the normal process of cell renewal in differentiated organs, or induced by the need to replace cells in injured tissues, is required for both the initiation and the development of neoplasia. The conversion of a normal cell into a neoplastic cell is believed to be a multistep process. It requires the accumulation of several genetic alterations that together are the determinants of the biological characteristics of neoplasia and malignancy. DNA damage and replication functions have not been precisely characterized. Without formal equations to subject to formal integration, it is possible to approximate the value of the risk function as a complex sum calculated from observations of the level of DNA damage and the rate of DNA replication occurring during several 1-h intervals after treatment with a carcinogen.
