Electrochemical Biosensor Based on Lectin-functionalized Nitrogen, Sulfur-doped Graphene Quantum Dot Decorated Gold Nanoparticles for Breast Cancer Diagnosis: From Academic Research to Clinical Translation

Breast cancer can develop when cells in the breast tissue undergo uncontrollable growth due to genetic, hormonal, environmental, and lifestyle factors. Genetic mutations, particularly in genes like BRCA1 and BRCA2, can increase susceptibility to breast cancer. In addition, hormonal influences, such as prolonged exposure to estrogen and progesterone, also contribute to cell proliferation. Environmental exposures, like radiation, along with lifestyle factors such as obesity and alcohol consumption, further elevate the risk. Abnormalities in cell growth and DNA damage can lead to the formation of tumors within the breast tissue. While some tumors may be benign, others can be malignant and potentially spread to other parts of the body [6]. It is important to note that not all breast tumors or abnormalities lead to cancer, and many breast cancers are treatable, especially when detected early through screening.

The rising complexity of diagnosing and treating breast cancer poses challenges across all resource settings. The advancement of cancer diagnosis systems is an urgent task for Worldwilde Health Organiation [7]. Implementing population-based screening programs for the early detection of asymptomatic disease emerges as a sensible strategy to reduce mortality. Nevertheless, these initiatives are costly and demand substantial resources. They also necessitate the establishment of comprehensive and quality-assured cancer services to effectively treat the identified diseases.

1.3. Conventional methods for breast cancer detection The traditional approach to breast cancer detection typically involves a combination of clinical breast examinations, imaging, and biopsy procedures. These methods have been the cornerstone of breast cancer screening for decades and have proven effective in detecting abnormalities in breast tissue [8, 9]. One of the most popular breast cancer detection methods is mammography. Mammograms are X-ray images of the breast that can detect early signs of breast cancer, such as lumps or calcifications, before they can be felt through a breast exam. Mammography is recommended as a screening tool for women starting at age 40, and it is considered the gold standard for detecting breast cancer in its early stages. Additionally, ultrasound and magnetic resonance imaging (MRI) may be used in conjunction with mammography for further evaluation or screening in certain cases, especially for women at higher risk or with dense breast tissue. Other popular methods include clinical breast examinations (CBE), where a healthcare provider manually examines the breasts for abnormalities, and breast self-exams (BSE), where women check their own breasts regularly for any changes. If suspicious abnormalities are detected through clinical examinations or imaging, a biopsy is performed to obtain tissue samples for analysis. There are various biopsy techniques, including: fine-needle aspiration (FNA), core needle biopsy (CNB), and surgical biopsy.

Conventional methods for breast cancer detection have several advantages, such as their proven effectiveness, widespread availability, and the ability to detect cancer at an early stage. They provide clear visualizations of tumors and facilitate tissue diagnosis through procedures like biopsies. Some methods are minimally invasive, reducing patient discomfort. However, these methods have limitations, including the potential for false results, exposure to radiation in imaging techniques, and invasive procedures that carry risks. Certain cancers may not be as effectively detected by these methods, and they can be expensive. Routine screening can lead to overutilization, unnecessary procedures, and patient anxiety. Moreover, these methods lack the precision of molecular information that is increasingly crucial for personalized treatment. They may not be suitable for large-scale population screening, and some cancers may have already metastasized before detection. To address these limitations, ongoing research explores the integration of molecular and genetic data to enhance diagnostic accuracy and tailor treatment decisions to individual patients.

1.4. ELISA for breast cancer detection Enzyme-Linked Immunosorbent Assay (ELISA) is a valuable tool in cancer detection and diagnosis. This highly sensitive and specific laboratory technique is based on the principles of antigen-antibody interaction and can be applied to various cancer-related biomarkers. Principally, ELISA relies on the specific binding of an antigen (a cancer-related protein or biomarker) in a patient's sample to an immobilized antibody on a solid surface. This interaction is then visualized using an enzyme-linked secondary antibody and a substrate that produces a detectable signal. ELISA can be customized to detect specific cancer biomarkers, such as prostate-specific antigen (PSA) for prostate cancer, carcinoembryonic antigen (CEA) for colorectal cancer, or CA-125 for ovarian cancer, and CA15-3 for breast cancer [10, 11]. Elevated levels of these biomarkers in a patient's blood or tissue can indicate the presence of cancer.