Theoretical mechanisms for synthesis of carcinogen-induced embryonic proteins: XV. Preliminary generalizations.

The term embryonic gene is discussed in which an operational definition is given, namely that it be restricted for those genes which are active during the embryonic state but repressed during differentiation. After generalizing a large variety of different types of carcinogenic agents and their action, which in principle are capable of activating embryonic genes, a preliminary notion of the carcinogenic process was derived. It appears that the bioalkylation pattern can be perturbed by a variety of agents from electromagnetic radiation to ethionine. Specific genes or their corresponding repressors such as an embryonic type phospho-protein kinase would become derepressed because of their methylation status (or by some other analogous alteration, e.g., via a specific mutation of a proto-oncogene that would create an embryonic type kinase, DNA intercalation by planar molecules, or, a hereditary process such as V-type position effect). This would cause competent stem type precursor cells containing easily derepressed or partially repressed arrays of embryonic genes to become activated, producing many features characteristic of a neoplastic cell.