Carcinogenesis describes the process that transforms a normal cell into a malignant cell. Knudsen studied the inheritance of retinoblastoma and theorized that carcinogenesis is a multistep process . He proposed the idea that two mutations are necessary for the development of retinoblastoma. Some individuals have an inherited predisposition to retinoblastoma, resulting in bilateral presentation at an early age. In this multifocal form, only one exogenous mutation is required, because the first mutation is inherited (Fig. 8-1A). In the sporadic form, the disease is unifocal and characterized by later onset (Fig. 8-1B). In this case, “two hits” must occur in the same cell—a much rarer event.
KeywordsEndometrial Cancer Thymine Dimer Nitro Amine Thorium Oxide Promoter Phorbol Ester
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