BT-474 Orthotopic Mouse Model Service for Breast Cancer

The BT-474 orthotopic mouse model replicates the HER2+⁺/ER+⁺/PR+⁺ luminal B breast cancer subtype within its native mammary tissue niche, enabling rigorous preclinical assessment of anti-HER2 agents, endocrine interventions, and combination strategies. Alfa Cytology delivers fully customizable BT-474 orthotopic programs—from model establishment and longitudinal tumor monitoring to comprehensive histopathological and molecular endpoint analysis—designed to accelerate your drug discovery pipeline with reproducible, publication-quality data.

Overview of BT-474 Orthotopic Mouse Model for Breast Cancer

BT-474 is a human breast ductal carcinoma cell line originally established in 1978 by Lasfargues and Coutinho from an invasive ductal carcinoma resected from a 60-year-old female patient. Genetically, the line is highly aneuploid with a modal chromosome number of approximately 55 and a hypertetraploid karyotype ranging from 91 to 111 chromosomes. When implanted orthotopically into the mammary fat pad of immunodeficient hosts such as nude (Nu/Nu) or NOD scid gamma (NSG) mice, BT-474 tumors recapitulate the architectural and stromal context of human breast cancer, permitting evaluation of primary lesion growth, local invasion, and metastatic dissemination to regional lymph nodes, lung, and liver.

Fig 1. BT-474 and other cell lines were orthotopically transplanted into immunodeficient mice. Circulating tumor cells (CTCs) were detected by size separation method. The CTC load in the BT-474 model was low (1.8±1.3 CTCs/mL). (Cleris, Loredana, et al., 2019)

Molecularly, BT-474 is classified as luminal B based on robust co-expression of estrogen receptor (ER^α), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/ErbB2). This triple-positive phenotype mirrors the most prevalent HER2+⁺ clinical subtype, in which estrogen-driven proliferation intersects with HER2 oncogenic signaling to promote aggressive disease and therapeutic resistance. The model is therefore indispensable for investigating HER2/ER pathway crosstalk, evaluating trastuzumab- or pertuzumab-based regimens, and exploring mechanisms of endocrine resistance in the context of HER2 co-amplification.

Cell Line Information: BT-474

BT-474 exhibits epithelial-like, adherent morphology with a propensity to form compact, grape-like clusters that rarely achieve full confluence. The line carries a TP53 mutation and displays a relatively slow doubling time of approximately 60–90 hours under standard culture conditions, necessitating careful handling during single-cell suspension preparation for in vivo applications.

Our Services

Alfa Cytology constructs and validates BT-474 orthotopic xenografts under rigorous preclinical quality standards, offering bespoke study designs that span tumor inoculation, bioluminescence or caliper-based growth tracking, pharmacokinetic sampling, and terminal histopathological evaluation to support your HER2-targeted or endocrine-combination therapeutic programs from lead optimization through mechanistic proof-of-concept.

Workflow of BT-474 Orthotopic Mouse Model Construction

BT-474 orthotopic model construction demands meticulous attention to cell dissociation, host selection, and surgical precision owing to the line's tight clustering morphology and relatively slow proliferation rate. The following protocol ensures high tumor engraftment efficiency and reproducible growth dynamics.

1. Cell Expansion and Authentication: Low-passage BT-474 cells are cultured to 70–80% confluence, authenticated by STR profiling, and confirmed for ER^α/PR/HER2 expression by flow cytometry or immunoblot prior to harvest.
2. Host Selection and Acclimatization: Female immunodeficient mice (Nu/Nu or NSG, 6–10 weeks) are quarantined, health-screened, and randomized by body weight to minimize baseline variability.
3. Single-Cell Suspension Preparation: Clusters are gently dissociated with trypsin-EDTA, triturated to disrupt aggregates, and passed through a 40 µm cell strainer; viability is confirmed by trypan blue exclusion (>98%).
4. Anesthesia and Surgical Site Preparation: Mice receive isoflurane inhalation anesthesia; the fourth mammary gland region is shaved, cleansed with alternating povidone-iodine and ethanol, and draped aseptically.
5. Orthotopic Cell Inoculation: A 1 × 10⁶ BT-474 cell suspension in 100 µL PBS/Matrigel is injected directly into the exposed mammary fat pad through a 27-gauge needle under direct visualization.
6. Wound Closure and Recovery: The skin incision is closed with sterile wound clips or sutures; postoperative analgesia is administered, and animals recover on a heated pad with continuous monitoring.
7. Tumor Monitoring and Randomization: Palpable tumors are measured twice weekly with digital calipers (V = 0.5 × L × W²); upon reaching 150–250 mm³, mice are randomized into treatment and vehicle-control cohorts.
8. Endpoint Harvest and Analysis: At study termination, primary tumors are excised, weighed, and imaged; draining lymph nodes, lungs, and liver are collected for metastasis assessment via histology, IHC, or molecular profiling.

Fig 2. BT-474 Orthotopic Mouse Model construction workflow.

Case Study-BT-474 Orthotopic Mouse Model Development

In a preclinical pharmacology program, the BT-474 orthotopic model was deployed to evaluate the efficacy of a dual HER2/ER-targeted combination regimen versus monotherapy controls. The study monitored primary tumor response kinetics, systemic biomarker modulation, and metastatic burden in regional lymph nodes and lung tissue, generating quantitative pharmacodynamic data to inform downstream candidate prioritization and dose-schedule optimization for luminal B breast cancer indications.

Why Choose Alfa Cytology?

Partnering with Alfa Cytology for your BT-474 orthotopic program means leveraging specialized expertise in hormone receptor-positive, HER2-amplified breast cancer modeling combined with rigorous quality assurance and flexible experimental design.

• HER2/HR Dual-Positive Proficiency: Deep experience modeling the complex signaling crosstalk inherent to ER+/PR+/HER2+ breast cancer subtypes.
• Orthotopic Surgical Excellence: Standardized mammary fat pad implantation protocols optimized for BT-474's cluster-forming morphology, ensuring high engraftment and consistent growth curves.
• Combination Therapy Evaluation: Proven capability to design and execute studies assessing anti-HER2 agents, endocrine therapies, and their synergistic combinations.
• Multimodal Endpoint Analysis: Integrated offerings spanning tumor volumetrics, bioluminescence imaging, multiplex IHC for ER/PR/HER2/Ki-67, and metastasis quantification.
• Adaptive Study Designs: Customizable treatment windows, dosing schedules, and genetically engineered host backgrounds to address specific mechanistic or translational hypotheses.

Contact Us

Whether you are advancing a novel HER2-targeted biologic, an endocrine combination strategy, or a resistance-overcoming small molecule, Alfa Cytology stands ready to support your preclinical objectives. Contact us today to discuss your BT-474 orthotopic study requirements, and our scientific team will tailor a program that aligns with your discovery milestones and regulatory expectations.

For research use only. Not intended for any clinical use.