Gene therapy vs. Dominant dissease.

[xoggyux]

Hi.
I am writing a term-paper about cancer treatment by gene therapy and I'd like to know a few things.
While writing my paper I thought that although gene therapy could introduce a working wild-type gene into a cell with a defective one, this would only help if the defective one did not have an adverse effect (for instance in case of non-functioning p53) however I saw no "easy" way how to avoid those genes that code for defective proteins that are always on and thus inducing the cancerous phenotype (such as Ras.)
Is there a walk around on this (I thought about adding a second gene that codes for a inhibitor protein though that would be extremely difficult to do, or just using gene therapy in conjunction with siRNA or perhaps any other drug.)
Please any insight would be appreciated. If plausible link some source so I can use it in my paper as reference.
Thank you.

[Jon Moulton]

While not cancer, there was a paper on using antisense oligos to suppress the dominant mutation causing myotonic dystrophy. The mutation repeated an RNA sequence that bound up an RNA binding protein required by other pre-mRNAs. The oligo blocked the repeat sequence, freeing up the RNA binding protein to do its job elsewhere.

Wheeler TM, Sobczak K, Lueck JD, Osborne RJ, Lin X, Dirksen RT, Thornton CA. Reversal of RNA dominance by displacement of protein sequestered on triplet repeat RNA. Science. 2009 Jul 17;325(5938):336-9.

[richiemedico]

Having a single gene disorder will result in single mutated genes and this mutated copy of gene will be responsible for a person to be affected by autosomal dominant disorder.