Table 1.

Chronological advancements in gene therapy approaches.

Year	Key Advancements	Ref.
1928	Griffith′s experiments with pneumococcal bacteria and introducing transforming principles	[17]
1944	Purification of transforming substance; first reported deoxyribonucleic acid (DNA) causes the transformation	[18]
1952	Transduction (transfer of genetic through bacteria) was introduced for the first time	[19]
1953	Double helix structure of DNA was described	[20]
1961	It was reported that viral infections can inherit genetic mutations	[21]
1962	First ever DNA-mediated heritable transformation of a biochemical trait	[22]
1973	First gene therapy trial conducted in humans	[23]
1989	Reported gene transfer in humans	[24]
1990	FDA approved gene therapy trial in humans for therapeutic applications.	[2]
1995	Gene therapy introduced for dental applications	[4]
1999	Jesse Gelsinger died during a clinical trial of gene therapy	[25]
2003	China approved gene therapy for clinical applications	[2]
2005	Gendicine™ (an adenoviral vector) approved for the treatment of squamous cell carcinoma	[26,27]
2009	Cerepro® (an adenoviral vector) gene therapy for the treatment of malignant brain tumors	[28]
2012	A gene therapy product (Glybera) that is an adeno-associated viral vector was recommended for the European Union	[2]