A Short Guide to CRISPR Cancer Research
Cancer is a global ailment with multiple forms, characterized by uncontrolled cell growth. It can be classified based on the affected tissue or cell type it originates from. Carcinomas, the most common type, arise from epithelial cells and have subcategories like adenocarcinoma and squamous cell carcinoma, while sarcomas form from bone or soft tissue, leukemias from blood cell-forming tissue, and lymphomas from immune system cells, including lymphocytes like T cells or B cells, and multiple myeloma begins in plasma cells. Amidst the search for effective cancer treatments, CRISPR-Cas9, a groundbreaking gene-editing tool, emerged in 2012.  It empowers researchers to make precise and efficient modifications to DNA sequences (knockouts, knock-ins, large insertions or deletions). CRISPR has enhanced researchers’ understanding of cancer biology and is offering potential avenues for innovative therapies. In this article, the link between CRISPR and Cancer Research will be explained through various applications of CRISPR to support cancer research from cancer genetics to precision disease modeling.
What links CRISPR to Cancer Research?
The intersection of CRISPR-Cas systems and Cancer Research lies in cancer genetics. This encompasses the genetic mutations causing uncontrolled cell growth, the engineered cell lines modeling various cancer types, and targeted gene therapies for treatment.
Cancer Genes Identification
Researchers use CRISPR to delve deeper into the role of gene function or mutation in cancer progression. Several cancer types exist, but few share common genetic mutations. These mutations either activate a gene (oncogene) or deactivate a gene (tumor suppressor), resulting in uncontrolled cell growth.
Cancer Drug Targets Detection
Despite common mutations activating oncogenes or deactivating tumor suppressor genes, there are limited targetable genetic drivers for tumor initiation and progression, complicating the efficiency of cancer treatment. Nowadays, scientists use CRISPR screens to pinpoint potential cancer-causing genes or targets. Large-scale genetic or small molecule screens enable the assessment of numerous genetic mutations or molecules, aiding in the identification of cancer-related genetic mutations and cancer drug targets.
Cancer Disease Cell Models
CRISPR-Cas9 complexes are commonly employed to engineer cancer cell lines, which include:
Immortalized Cell Lines
Immortalized cancer cell lines, derived from tumors, can grow indefinitely in 2D cultures under specific conditions. They're frequently used in studying cancer biology and testing potential treatments due to their scalability and ease of use. However, their physiological relevance to actual cancer remains debated.
Primary Cell Lines
Primary cell lines, directly isolated from tissue, increasingly serve as model systems for cancer research. They more closely represent the original organism compared to continuously propagated cell lines.
3D organoid cultures, offering a more comprehensive model, are used to replicate physiologically significant events in tumor formation. 
Challenges & Perspectives in CRISPR Cancer Research
CRISPR/Cas technologies have been applied to disease modeling, gene therapies, transcription modulation, and diagnostics.  However, issues like potential immunological reactions and off-target effects persist. To address these, several innovative CRISPR/Cas tools and methods have emerged.
Off-target effects, resulting from unintended Cas9 protein cleavage in non-target sequences, have been a primary concern since CRISPR's inception. These effects can range from gene function loss to carcinogenesis. To mitigate this, scientists have employed bioinformatics tools (like gRNA design and off-target prediction software) and alternate biochemical components (such as Cas9 nickases and anti-CRISPR proteins). 
A notable advancement involves the controlled release of RNP complexes directly into the nucleus. This not only minimizes off-target effects but also curbs immune responses and cytosolic degradation, making it more efficient and precise than traditional methods.
CRISPR has proven to be a powerful tool in the development of cancer therapeutics. In its infancy, many skeptics were concerned with the off-target effects of this technology. However, research over the years has shown the efficacy and specificity of using CRISPR in cancer research, notably to identify cancer gene function and drug targets, and to develop reliable cancer disease models. While scientists are not saying CRISPR is the cure to cancer just yet, promising results from studies around the world indicate that it may be a powerful weapon in the fight against cancer in the future.
 Jinek, Martin, et al. "A programmable dual-RNA–guided DNA endonuclease in adaptive bacterial immunity." Science337.6096 (2012): 816-821.
 Dutta, Devanjali, Inha Heo, and Hans Clevers. "Disease modeling in stem cell-derived 3D organoid systems." Trends in molecular medicine 23.5 (2017): 393-410.
 Hryhorowicz, M., Lipiński, D., & Zeyland, J. (2023). Evolution of CRISPR/Cas Systems for Precise Genome Editing. International Journal of Molecular Sciences, 24(18), 14233.
 Naeem, M., Majeed, S., Hoque, M. Z., & Ahmad, I. (2020). Latest developed strategies to minimize the off-target effects in CRISPR-Cas-mediated genome editing. Cells, 9(7), 1608.