The Key Role Of Breast Biopsy in Histological Molecular Subtyping

https://www.mayoclinic.org/tests-procedures/breast-biopsy/about/pac-20384812

Breast biopsy procedures have long transcended the simple realm of "diagnosis"; they are an essential gateway to personalized precision treatment. In the modern concept of comprehensive breast cancer management, the few small tissue samples obtained through puncture carry a wealth of information that determines the patient's quality of life. This article will explore in depth how breast biopsy procedures, through high-quality sample collection, empower subsequent molecular pathological analysis and treatment decisions.

Sample Quality: The Cornerstone of Molecular Detection

Whether it's immunohistochemical testing of hormone receptors (ER/PR) and HER2 status, or gene expression profiling using Oncotype DX and MammaPrint, stringent requirements are placed on the integrity, timeliness of fixation, and tumor cell content of tissue samples. In breast biopsy procedures, tissue strips obtained using 14G or larger diameter needles better meet these requirements compared to cytological specimens obtained through fine-needle aspiration.

* Structural Preservation: Core needle biopsy preserves the original structure of the mammary ducts, helping pathologists differentiate between carcinoma in situ and invasive carcinoma, which is crucial for determining treatment plans (such as whether axillary lymph node dissection is necessary).

* Tumor Prevalence: To obtain reliable molecular detection results, the proportion of tumor cells in the sample typically needs to reach a certain level (e.g., 20%-30%). Vacuum-assisted biopsy (VAB) systems, due to their larger sampling slots, often provide samples with higher tumor cell content, making them particularly suitable for highly heterogeneous tumors.

Prospective Applications of Needle Design in Molecular Analysis

Advanced breast biopsy procedures are beginning to consider the needs of downstream molecular analysis:

• 1. RNase/DNase-free treatment: Some high-end disposable needles employ special packaging and processing techniques to avoid exogenous nuclease contamination and protect RNA integrity, which is crucial for samples requiring RNA sequencing or gene chip analysis.
• 2. Tissue preservation solution compatibility: The needle material (especially polymer materials) must ensure it does not chemically react with formalin or other tissue fixatives to avoid affecting subsequent antigen retrieval processes.
• 3. Marker retention: In vacuum-assisted biopsy, some systems can leave a titanium clip (marker) before needle removal. This is not only for marking the biopsy site for subsequent surgical resection, but may also enable therapeutic integration in the future by loading drugs or sensors onto the titanium clip surface.

Biopsy Strategies in Special Cases

For certain types of breast cancer, such as inflammatory breast cancer or Paget's disease, the implementation of breast biopsy procedures is particularly critical. In these cases, multiple punctures may be necessary to ensure sufficient tumor tissue is obtained. Furthermore, performing a biopsy before neoadjuvant therapy (chemotherapy/targeted therapy) to establish baseline molecular typing is irreplaceable for assessing treatment efficacy (e.g., PCR, pathological complete response).

The Complement and Challenges of Liquid Biopsy

While tissue biopsy remains the gold standard, liquid biopsy (circulating tumor DNA, ctDNA) has developed rapidly in recent years. However, current clinical guidelines still emphasize that no liquid biopsy result can replace traditional breast biopsy procedures for definitive diagnosis and molecular typing. The biopsy tissue provides information on the spatial heterogeneity of the tumor, while liquid biopsy reflects more of the dynamic changes in the tumor throughout the body. Combining both is the future trend.

In conclusion, breast biopsy is the starting point for modern precision medicine in breast cancer. Each biopsy is like marking key coordinates on a patient's "life map." Therefore, clinicians must have a "holistic view" when choosing the biopsy needle and procedure, considering not only the current diagnosis but also the treatment needs for the next few years. High-quality biopsy samples are the best gift for pathologists and oncologists.