In children with adenosine deaminase deficiency, the autologous transplantation of genetically modified hematopoietic stem cells was reported to lead to severe immunodeficiency followed by acute leukemia in some of the patients. Nerve cells implantation in Parkinson’s disease patients was reported the high rate of severe and uncontrollable dyskinetic activity as adverse effect. Also, myoblast implantation into the heart tissue showed adverse event of increased rates of cardiac arrhythmias. This evidence concerns the gene ADA and acute leukemia.