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Cancer is one of the most leading causes of mortality all over the world and remains a foremost social and economic
burden. Mutations in the genome of individuals are taking place more frequently due to the excessive progress of
xenobiotics and industrialization in the present world. With the progress in the field of molecular biology, it is
possible to alter the genome and to observe the functional changes derived from genetic modulation using geneediting technologies. Several therapies have been applied for the treatment of malignancy which affect the normal
body cells; however, more effort is required to develop some latest therapeutic approaches for cancer biology and
oncology exploiting these molecular biology advances. Recently, the clustered regularly interspaced short
palindromic repeats (CRISPR) associated protein 9 (Cas9) system has emerged as a powerful technology for cancer
therapy because of its great accuracy and efficiency. Genome editing technologies have demonstrated a plethora of
benefits to the biological sciences. CRISPR-Cas9, a versatile gene editing tool, has become a robust strategy for
making alterations to the genome of organisms and a potent weapon in the arsenal of tumor treatment. It has
revealed an excellent clinical potential for cancer therapy by discovering novel targets and has provided the
researchers with the perception about how tumors respond to drug therapy. Stern efforts are in progress to enhance
its efficiency of sequence specific targeting and consequently repressing off-target effects.CRISPR-Cas9 uses
specific proteins to convalesce mutations at genetic level. In CRISPR-Cas9 system, RNA-guided Cas9 endonuclease
harnesses gene mutation, DNA deletion or insertion, transcriptional activation or repression, multiplex targeting only
by manipulating 20-nucleotide components of RNA. Originally, CRISPR-Cas9 system was used by bacteria for their
defense against different bacteriophages, and recently this system is receiving noteworthy appreciation due to its
emerging role in the treatment of genetic disorders and carcinogenesis. CRISPR-Cas9 can be employed to promptly
engineer oncolytic viruses and immune cells for cancer therapeutic applications. More notably, it has the ability to
precisely edit genes not only in model organisms but also in human being that permits its use in therapeutic
analysis. It also plays a significant role in the development of complete genomic libraries for cancer patients. In this
review, we have highlighted the involvement of CRISPR-Cas9 system in cancer therapy accompanied by its
prospective applications in various types of malignancy and cancer biology. In addition, some other conspicuous
functions of this unique system have also been discussed beyond genome editing.