The Application of CRISPR Technology in Breast Cancer

Jingyi Hu

, Chengyue Wang

and Zhuoer Yang

Zhengzhou NO.7 High School, Zhengzhou, Henan, China

Suzhou Science and Technology Town Foreign Language High School, Suzhou, Jiangsu, China

Keywords: CRISPR‑Cas9, Breast Cancer, Gene Editing.

Abstract: With the continuous progress of the times and the rapid development of science and technology, CRISPR

technology has also undergone the test of time and gradually demonstrated its convenience and

professionalism. In the detection of breast cancer (BC), the scientific application of CRISPR technology can

significantly enhance the efficiency and quality of detection. This paper focuses on an in-depth exploration

of the practical applications of CRISPR technology in breast cancer detection and provides a detailed

introduction to the pathological mechanisms of breast cancer. However, the discussion in this paper is limited

to the application of CRISPR technology in this specific field; thus, the conclusions and perspectives

presented may carry a degree of subjectivity and one-sidedness. Additionally, the technology itself still faces

unresolved challenges and inherent limitations. Expanding the application of gene editing technology in BC

detection will facilitate earlier medical intervention to improve patient recovery rates and, to some extent,

stimulate economic growth. While this research offers valuable empirical references for future studies, certain

technical issues remain unresolved. Future investigations should prioritize addressing these technological

constraints for refinement.

1 INTRODUCTION

CRISPR technology is widely applied in modern

society and holds significant research potential.

Currently, there are substantial gaps in the existing

research on CRISPR technology. It’s a repetitive

structure widely distributed in the genomes of

bacteria and archaea, providing immunity to

prokaryotes during their resistance to phages or other

pathogens (Wang et al., 2017). Meanwhile, breast

cancer (BC) is one of the most prevalent cancers

among women worldwide. In 2018 alone, the global

incidence and mortality rates of this cancer among

women were 46.3/10⁵ and 13.0/10⁵, respectively, with

an upward trend (Bray et al., 2018). It is caused by the

uncontrolled proliferation of epithelial cells in the

breast. Integrating CRISPR technology into the BC

detection process would facilitate early cancer

detection and timely intervention. Currently, most

existing treatment options involve drug therapy or

surgery, which can have significant impacts on the

body, potentially causing side effects such as

vomiting and weakened immunity (Trayes et al.,

2021). Optimizing detection methods and enabling

early intervention could reduce mortality risks,

alleviate societal pressures to some extent, and

strengthen social stability. CRISPR enables the

editing of target genes, allowing for the deletion or

addition of specific DNA segments. It also offers

advantages such as simplicity of operation, low cost,

and high efficiency (Wang et al., 2017). Its

application in BC detection and treatment could

theoretically enable direct or indirect modification of

pathogenic genes at the DNA level, with additional

benefits such as low error rates and high efficiency,

allowing for precise detection, deletion, or

replacement of pathogenic genes. This process could

also be extended to other related diseases, providing

valuable references.

This paper aims to summarize the applications of

CRISPR technology in BC detection and treatment,

including an introduction to CRISPR technology, its

usage, and its principles, while also highlighting its

limitations. It reviews current applications and looks

to the future, providing reference value and support

for researchers in related fields, thereby potentially

improving the cure rates of other diseases to some

extent.

100

Hu, J., Wang, C. and Yang, Z.

The Application of CRISPR Technology in Breast Cancer.

DOI: 10.5220/0014401500004933

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 1st International Conference on Biomedical Engineering and Food Science (BEFS 2025), pages 100-104

ISBN: 978-989-758-789-4

2 PATHOGENESIS OF BC

The onset of BC is directly related to estradiol and

estrone. Early menarche, late menopause, infertility

and late first childbirth, short breastfeeding time, and

estrogen replacement therapy after menopause can

prolong the exposure of estrogen in the body and are

closely related to the onset of BC. At the same time,

genetic factors are also high-risk factors for BC. If

there is a history of BC in first-degree relatives, the

risk of developing the disease is two to three times

that of ordinary people. Gene mutations can also

increase the risk of BC. Physical factors such as chest

radiotherapy can also cause the occurrence of BC.

2.1 Epidermal Growth Factor

Receptor (EGFR)

As people continue to deepen their understanding of

the pathogenesis of BC, studies have found that

members of the growth factor family such as

epidermal growth factor and vascular endothelial

growth factor play an important role in the occurrence

and metastasis of BC. PGRN, as a member of the

growth factor family, has also been confirmed to be

abnormally expressed in a variety of epithelial

tumors, regulating the occurrence and development of

tumors, but there are few reports on the regulatory

effect of PGRN on BC. This study found that PGRN

was significantly upregulated in BC tissues through

immunohistochemistry detection, and was positively

correlated with EGFR expression.

This suggests that there may be some association

between the two in BC, and the mechanism of PGRN

regulating BC may be related to EGFR. EGFR is

encoded by the EGFR gene located on chromosome

7. When EGFR binds to ligands such as EGF, EGFR

will undergo homodimerization or

heterodimerization, and can regulate and transfer the

life activities of cells through internal signal

transduction pathways, and it is concluded that PGRN

is an important conclusion in the occurrence and

development of tumors.

In BC-related studies, it was found that PGRN has

an effect on tumor cells. Due to excessive production

of ligands, upregulation of EGFR transcription levels,

EGFR mutations, and EGFR gene amplification,

EGFR constitutive activation will lead to excessive

cell proliferation (Li, et al., 2020). In BC tissues, the

positive expression rate of EGFR is high, especially

in triple-negative BC. It is reported that more than

50% of triple-negative BC have high expression, but

antibody drugs targeting EGFG have not achieved

good results in treating BC patients.

Therefore, studying the molecular mechanism of

EGFR function in BC may provide direction for the

future clinical treatment of BC. PGRN is a secretory

cell growth factor with multiple functions. PGRN is

involved in a variety of physiological and

pathological processes, including cell proliferation,

angiogenesis, and damage repair (Li, et al., 2020).

According to studies in tumor cells, reducing the level

of PGRN mRNA can greatly slow down tumor cell

proliferation, and also plays a major role in the

growth of triple-negative BC cells. When PGRN is

reduced, the proliferation and cloning ability of BC

cells decreases, and the volume of the formed tumor

is about 90% smaller than that of the parent tumor

cells of PGRN (Mahmoudian, et al., 2022).

2.2 Human Epidermal Growth Factor

Receptor 2 (HER2)

One of the more extensively researched BC genes to

date, HER2 was independently identified by three

research teams in the 1980s. The HER2 gene is a key

target for the selection of targeted therapy

medications for BC in addition to being a prognostic

indication for clinical treatment monitoring. Serum

HER2 may be an independent prognostic factor that

influences the therapeutic outcome. It is linked to the

lymph node status and tumor burden HER2 of BC

patients.

Compared with the low-level TIL group, the high-

level group of invasive BC was HER2-positive, with

a high proportion of round/elliptical, smooth edges,

and ring enhancement on MRI, while the proportion

of peritumoral edema was low. JIA observed breast

ductal carcinoma in situ and DCIS with micro

invasiveness and proposed that high levels of BCTIL

are associated with HER2 overexpression. Another

study (Zhou, et al., 2021) showed that BC with high

TIL levels is more likely to show characteristics such

as round/elliptical and smooth edges. Studies have

shown that high TIL BC has a high proportion of

uneven enhancement, and enhancement pattern and

ADC value are independent predictors of BCTIL

levels. Some researchers believe that BCTIL levels

are not related to peritumoral edema (P=0.16), which

may be related to mechanical obstruction of the local

lymphatic vascular system leading to fluid retention

or leakage in the peritumoral space. ADC value can

quantitatively evaluate the diffusion of water

molecules in the tumor; T1 value can potentially

quantitatively evaluate the intrinsic characteristics of

The Application of CRISPR Technology in Breast Cancer

101

the tumor. The average ADC value of BC with high

TIL level is higher than that of those with low TIL.

ÇELEBI et al. found that BCTIL level was positively

correlated with its ADC value; Guo Yi et al. believed

that the average ADC value of BC was weakly

negatively correlated with its Ki-67 expression level

(Park, et al., 2021).

2.3 Editing Principle of CRISPR-Ca9

A single guide RNA and a Cas protein make up the

ribonucleoprotein complex that makes up the

CRISPR/Cas system. By using complementary guide

RNAs to activate Cas enzymes, the system starts a

trans-cutting process that breaks down random

single-stranded DNA in a targeted manner. A

CRISPR array with only a few hundred palindromes

makes up the entire CRISPR/Cas locus. 30–40 bp

spacers are used to separate these exact repeat

sequences. The operon contains clusters of Cas genes,

which encode effector and adaptability modules as

well as a few auxiliary genes. The mechanism of

action of CRISPR/Cas includes the following three

stages:

a. Adaptation stage: incorporation of the spacer

into the host genome, that is, capturing and

integrating a piece of foreign virus or plasmid DNA

into the CRISPR sequence array as a new spacer

sequence;

b. Expression stage: pre-CRISPR RNA

transcription and processing, that is, the transcribed

crRNA combines with the auxiliary RNA to form a

mature gRNA, ready to participate in subsequent

DNA recognition and cutting;

c. Interference stage: the target genetic element is

destroyed by the crRNA-Cas protein effector

complex due to the semi-independent evolution of

different modules.

The classification of CRISPR/Cas systems is a

complex issue. Existing CRISPR/Cas system

classifications use a variety of criteria, including

characteristic Cas genes, organization of Cas operons,

and phylogeny of conserved Cas proteins. The

generally accepted view is to divide all CRISPR/Cas

systems into two categories, 6 types, and 33 subtypes.

Class I systems are types I, III, and IV, with multi-

subunit effector complexes composed of several Cas

proteins, while in Class II, they are types II, V, and

VI, and the effector is a single large multi-domain

protein. These subtypes differ in subtle differences in

site organization and usually encode subtype-specific

Cas proteins. Type I, II, and V systems recognize and

cut DNA, type VI targets RNA, and type III cuts DNA

and RNA. Class II is widely used in basic and

translational medicine research because it is easier to

operate as a single nuclease protein structure.

3 APPLICATION PROGRESS

3.1 Diagnosis

There are many ways to detect BC. Doctors usually

use molybdenum target, nuclear magnetic resonance

and manual examination to diagnose BC.

Molybdenum target, the full name of it is

mammography, is an imaging technology widely

used in the diagnosis of breast diseases (Chen, 2025),

which is mostly used to diagnose carcinoma in situ

and early cancer. Its principle is that breast

molybdenum target examination is an examination

method that uses X-ray to penetrate breast tissue for

imaging and displays abnormalities through tissue

density differences (Chen, 2025). Observe whether

there are clustered calcifications in this way, and then

confirm the diagnosis.

In addition, there is magnetic resonance imaging

(MRI). Nuclear magnetic resonance technology uses

the spin motion characteristics of non-zero magnetic

moment atomic nuclei in a magnetic field for

imaging. The phase change of atomic nucleus

movement is analyzed to realize the measurement of

three-dimensional velocity in space (Zhang, et al.,

2025).

In addition, according to the doctor's manual

examination, since BC is a solid tumor and the breast

is exposed on the body surface rather than viscera, it

is easy to find the mass through the manual

examination if there is a lesion, so as to find the

lesion.

In addition to accurate detection methods, B-

ultrasound is the main means of normal checkup. Its

advantages are low cost, little damage to the body and

short operation time. However, it can not confirm the

diagnosis of BC, and further examination is needed if

abnormalities are found.

3.2 Treatment

3.2.1 Conventional Therapy and Its

Disadvantages

The conventional therapy of BC refers to surgery,

chemotherapy and radiotherapy. Surgery is difficult

to remove all lesions in the body of patients with

advanced stage, and it is unable to treat metastatic

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cancer or even accelerate the spread of cancer,

causing great loss to the body. Chemotherapy can be

used to eliminate systemic cancer, but at the same

time of eliminating cancer cells, some normal cells

will also be eliminated, which may lead to hair loss,

nausea, decreased immunity, decreased anticoagulant

function, anemia and so on. Besides, it brings greater

consumption of the body. Radiotherapy can only be

used to eliminate local lesions, but it is also easy to

bombard DNA, causing secondary cancer. The above

three conventional therapies have certain drawbacks,

so now there are many new therapies to replace or

assist

3.2.2 CAR-T Immunotherapy

Car-t immunotherapy aims to activate the immune

system to attack cancer cells. Car-t consists of

chimeric antigen receptor (car) and T cells. The

principle is to extract T cells from patients' blood and

combine them with car protein through gene editing,

so that it can accurately target and recognize cancer

cells and distinguish normal cells, and induce the

immune system to attack cancer cells. At the same

time, car-t still has many side effects, such as the high

activation and proliferation of car-t cells stimulated

by tumor associated antigens, the interaction with

surrounding cells to activate the immune system at

the same time of killing tumor cells, and the positive

feedback cycle of cytokines produced induces a series

of cells to release cytokines to strengthen the

inflammatory response, leading to the occurrence of

CRS （ Cytokine Release Syndrome ） . Car-t

immunotherapy has bipolarity in clinical practice,

which shows that patients who are sensitive to

immunotherapy will get much better, and tumors will

be gradually eliminated, but many patients have no

response to this medical method.

3.2.3 Monoclonal Antibodies (mAbs)

MAb drugs, such as trastuzumab, are mAbs against

HER-2, that is, highly homogeneous antibodies

produced by a single B cell clone that only target a

specific epitope. By occupying the site, it effectively

prevents human epidermal growth factor from

attaching to HER-2 and reduces the overexpression,

thereby inhibiting the growth of cancer cells (Liu,

2025).

BC is a solid tumor. According to the different

conditions of patients, the combined treatment of

surgery, chemotherapy, radiotherapy and

immunotherapy is usually adopted. Therefore,

targeted assistance of gene editing technology is

crucial. This therapy aims to reduce the occurrence of

cancer metastasis and recurrence, which can be

effectively matched according to the situation of

different patients, so as to minimize damage and

maximize treatment.

4 CONCLUSION

This paper delves into the practical applications of

CRISPR technology in breast cancer (BC) detection

and provides a detailed explanation of its underlying

mechanisms. Additionally, the study analyzes the

pathological mechanisms of BC and highlights the

potential of CRISPR technology in BC detection

through research. The findings suggest that

expanding the application of CRISPR technology in

BC detection could significantly reduce the mortality

risk for breast cancer patients and alleviate the

economic burden associated with treatment, thereby

offering greater security for families, promoting

social harmony and stability, and driving economic

development.

The experience gained from applying CRISPR

technology in BC detection not only provides

valuable insights for genetic testing in other related

fields but also offers innovative solutions to common

challenges in genetic detection. However, the current

application of CRISPR technology still faces certain

limitations. For instance, the precision of detection

needs further improvement, and the operational

procedures remain relatively complex, issues that

require additional research and refinement.

Moreover, while CRISPR technology is primarily

utilized in detection, its efficacy in actual therapeutic

applications is still limited, which somewhat restricts

its broader potential. Nevertheless, with continuous

technological advancements and new scientific

breakthroughs, it is anticipated that these challenges

will be effectively addressed in the near future,

paving the way for broader clinical applications of

CRISPR technology.

AUTHORS CONTRIBUTION

All the authors contributed equally and their names

were listed in alphabetical order.

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103

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