BCL11A and sickle cell disease: CRISPR/Cas9 gene therapy targeting BCL11A (BCL11 transcription factor A) has been approved to treat sickle cell disease,86 which encouraged CRISPR/Cas9 therapies for other diseases resulting from specific gene mutations like PIK3CA. Yet, the formidable challenges lie in the delivery technology and in vivo application of CRISPR/Cas9 gene editing when it comes to treating solid tumors.