Which of the Following Statements Is FALSE Regarding Gene Therapy

Which of the following statements is FALSE regarding gene therapy?

A) Approaches with iPS cells avoid problems of immune system incompatibility, but are limited to diseases, like blood disorders, in which cells can be isolated, corrected, and reintroduced.
B) The integration of a transgene into the genome of the target cell by a viral vector is not permanent, and therefore it will require repeated treatments.
C) iPS cells that continue to express the Yamanaka factors are predisposed to become cancerous.
D) Both somatic and germinal gene therapy have been successful in animal systems; but for ethical reasons, only somatic gene therapy has been attempted in humans.
E) The insertion of a vector may cause a detrimental mutation.