Do you know what extension he's on? http://xnxxarab.site/ homemadeporn The results are encouraging, says Uta Griesenbach, a gene therapist at Imperial College London. âEven after fairly long-term follow up, it appears to be safe and effective.â The boys arenât out of the woods yet â some of the patients in the original gene therapy trials didnât develop cancer until four years after treatment. But Griesenbach says that the children in the new studies donât have warning signs of cancer.