Human Breast Cancer Antigen (CA 15-3)

CA 15-3 (cancer antigen 15-3) is a cell surface glycoprotein encoded by the MUC1 gene, widely present on the surface of various epithelial cells, and is overexpressed in 90% of breast cancer cases. Breast cancer is one of the most common malignant tumors among women globally and a leading cause of cancer-related deaths in women. Each year, over 2 million women are diagnosed with breast cancer, with approximately 400,000 deaths resulting from the disease. The incidence of breast cancer is highest in North America, Australia, New Zealand, Western Europe, and Northern Europe, while it is lower in Asia and sub-Saharan Africa. These differences are closely related to cultural and environmental changes brought about by industrialization, such as increased fat intake, weight gain, earlier age at menarche, shorter breastfeeding periods, and changes in reproductive patterns, including fewer pregnancies and delayed age at first childbirth. For patients diagnosed with breast cancer, accurately defining and monitoring the disease status is crucial, as the results of diagnostic tests directly influence treatment plans and prognosis. Improved diagnostic tests and management methods based on various biomarkers have significantly reduced breast cancer mortality rates.

CA 15-3 is an essential tumor marker for the diagnosis and surveillance of breast cancer. First, the expression of CA 15-3 in breast cancer patients causes the development of antibodies (anti-CA 15-3), which is important for cancer prediction and prognosis. Elevated CA 15-3 levels can be used to predict the probability of recurrence in breast cancer patients, as well as to monitor response to advanced treatment. Studies have shown that the normal range of CA 15-3 levels in healthy individuals is typically no more than 30 U/mL, whereas in 30-50% of breast cancer patients, CA 15-3 levels are significantly elevated. If the CA 15-3 concentration exceeds 100 U/mL, it is generally considered indicative of disease. The detection of serum tumor markers (CA 15-3 and CEA) can identify metastasis in up to 60-80% of breast cancer patients early, and the combined measurement of both markers can detect 40-60% of recurrences 2-18 months before clinical or radiological evidence appears. Regular assessment of serum CEA and CA 15-3 levels is crucial for predicting prognosis and developing optimal treatment plans. CA 15-3 levels are usually higher in advanced breast cancer patients than in early-stage patients, with CA 15-3 sensitivity superior to that of CEA. Studies have indicated that 20-30% of early breast cancer patients will eventually develop distant metastatic disease recurrence, with recurrence risk closely related to the initial presentation stage and the tumor's underlying biological characteristics.

Current research and application trends regarding CA 15-3 mainly focus on its detection methods and other applications. Traditional CA 15-3 detection methods include mass spectrometry, surface-enhanced Raman scattering, high-performance liquid chromatography, and high-performance thin-layer chromatography. However, these methods are often expensive, slow, and complex to operate. In recent years, biosensors have been considered an ideal alternative to traditional detection techniques in clinical and near-patient testing. Biosensors offer advantages such as specificity, selectivity, sensitivity, and high mobility, with low sample preprocessing thresholds. Electrochemical biosensors can simultaneously detect multiple biomolecules, featuring excellent responsiveness and selectivity, durability, real-time measurement, cost-effectiveness, and time-saving preparation, making them ideal tools for monitoring biomarkers. Additionally, CA 15-3 not only plays a significant role in breast cancer but also has notable applications in other cancer types such as ovarian cancer, non-small cell lung cancer, and colorectal cancer. For example, in ovarian cancer patients, particularly those with advanced disease, CA 15-3 levels are significantly elevated and can enhance the utility of CA125 (the primary serum marker for ovarian cancer). Therefore, as a widely used biomarker, the detection methods and application fields of CA 15-3 continue to expand and optimize.

Figure 1. Schematic diagram of the recognition principle of molecularly imprinted polymer (MIP) sensors for CA 15-3 detection (Source: Ribeiro JA, et al. 2018)

Carcinoma Antigen 15-3
Cancer Antigen 15-3
CA15-3
Breast Cancer Antigen 15-3