Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA can be inserted into or adjacent to a cellular proto-oncogene. Insertion of the provirus can cause mutations by interrupting coding sequences or regulatory elements, or cause unregulated expression of the proto-oncogene resulting in tumor formation.
