Cancer is not due to the expression of introns

Current evidence indicates that the neoplastic phenotype results from either an increased expression of normal cellular genes, or a small modification in the normal cellular gene product. These oncogenes appear to have conventional gene structure, in that introns are splice out. These observations strongly argue against the hypothesis that the neoplastic phenotype results from the expression of introns which are repressed in "normal" body cells. In addition the vast majority of known intron sequences preclude their translation.