๐ป Code of LifeCancer treatment and research communications
AI and Molecular Biomarker Integration: Reshaping the Landscape of Breast Cancer Diagnosis and Personalized Treatment
## Background
Breast cancer is a heterogeneous disease characterized by significant differences in molecular profiles and treatment responses, even within the same organ. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) are established biomarkers that guide decisions regarding endocrine therapy and HER2-targeted treatment. BRCA1 and BRCA2 mutations are relevant for assessing hereditary risk and for the use of poly(ADP-ribose) polymerase (PARP) inhibitors.
However, conventional classification alone is insufficient to fully explain tumor evolution and drug resistance. Even within the same HR-positive or HER2-positive breast cancer subtype, treatment outcomes and recurrence patterns can vary. Furthermore, biopsies, which involve sampling only a portion of the tumor, may not fully capture intratumoral heterogeneity. Image interpretation can also be influenced by factors such as breast density, imaging equipment, and the experience of the radiologist. To address these limitations, researchers have integrated recent advances in molecular biology, artificial intelligence (AI), and precision medicine. This review provides a comprehensive overview of breast cancer biomarkers, diagnostics, and treatment strategies, rather than presenting the results of a clinical study involving a new patient cohort.
## Key Findings
The review describes the breast cancer decision-making process as a combination of 'established and novel biomarkers.' While ER, PR, HER2, and BRCA mutations currently guide treatment decisions, alterations in tumor suppressor genes such as TP53, PTEN, and STK11 are presented as potential markers for more detailed interpretation of tumor behavior and resistance mechanisms. However, these three genes are not yet established as independent criteria for treatment decisions across all breast cancers. Their prognostic value and predictive ability for treatment response should be prospectively validated in specific cancer subtypes.
In the diagnostic arena, machine learning and deep learning are being applied to medical imaging, including mammography, to identify subtle lesions. These technologies are also being integrated into multimodal systems that combine clinical information, imaging data, and genomics. This approach differs from traditional methods that rely on single images or biomarkers by calculating the correlations between different data layers to support early detection, diagnostic assistance, and risk stratification. The abstract does not provide specific performance metrics such as accuracy or sensitivity, the size of the training dataset, or the names of specific AI models. Therefore, the improvements in diagnostic performance should be interpreted as a general trend, rather than as evidence of the clinical superiority of a specific algorithm.
The therapeutic landscape has also expanded. In addition to surgery and cytotoxic chemotherapy, treatment strategies now include endocrine therapy, immunotherapy, targeted therapy, antibody-drug conjugates (ADCs), and gene-based approaches. In advanced breast cancer, cyclin-dependent kinase 4/6 (CDK4/6) inhibitors, PARP inhibitors, phosphoinositide 3-kinase (PI3K) inhibitors, and selective estrogen receptor degraders (SERDs) have emerged as important targeted therapies. Each of these agents is selected based on the patient's hormone receptor status, genetic mutations, and prior treatment history and response.
## Significance and Future Directions
The key concept presented in this review is that AI should serve as a decision-support tool for physicians, rather than replacing them with automated diagnostic systems. By highlighting suspicious lesions in images and integrating this information with pathology and genomic data, AI can improve the consistency of patient selection and treatment sequencing. Nanotechnology-based drug delivery systems offer a strategy to increase drug exposure in the tumor and reduce toxicity to normal tissues. CRISPR/Cas9 is expected to be a valuable tool for identifying resistance genes and validating therapeutic targets.
Several challenges remain before these technologies can be widely implemented in clinical practice. AI systems must be validated in external datasets to ensure that their performance is maintained across different hospitals, patient populations, and imaging equipment. The potential for bias in training data and the lack of transparency in decision-making algorithms must also be addressed. CRISPR/Cas9 therapy faces challenges related to off-target editing, tumor cell delivery efficiency, and long-term safety. Nanocarriers must meet requirements for in vivo distribution, manufacturing reproducibility, and large-scale production. Given the lack of direct comparative trials or survival data in the review, it is important to distinguish between the technologies presented as established clinical standards and those that are still in the development stage. The actual adoption of these technologies will depend on prospective studies that evaluate not only accuracy but also survival, reduction in unnecessary tests, toxicity, and cost-effectiveness.