Chromosomal rearrangement and carcinogenesis.

All carcinogens that have been thoroughly tested have been found to induce some kind of chromosomal rearrangement. Chromosomal rearrangements are associated with a variety of human and rodent cancers and are associated, with in vitro cell transformation. The DNA from non-malignant cells can transform other non-malignant cells under conditions that may involve chromosomal rearrangement. These findings support the view that chromosomal rearrangement can be a step in carcinogenesis. Available evidence indicates that carcinogens can act to induce chromosomal rearrangement by creating or revealing sites on DNA for recombination, or by inducing or activating cellular systems resulting in a stimulation of recombination. Chromosomal rearrangement may affect carcinogenesis by altering gene expression. Perhaps by allowing the activation of cellular cancer genes.