Service Overview
Antibody-drug conjugates (ADCs) rely on selective target antigen expression on tumor cells to deliver cytotoxic payloads with minimal off-target toxicity. However, target expression can be heterogeneous and dynamic across patients and during therapy, underscoring the need for reliable, real-time quantification. Traditional tissue biopsies provide only a static snapshot and are often infeasible for longitudinal monitoring. Our ADC Drug Target Expression Analysis Service addresses this gap by enabling quantitative measurement of ADC targets—such as TROP2 and HER2—directly on circulating tumor cells (CTCs) isolated from routine blood draws.
Using validated immunophenotyping and image-based analysis, we deliver per-cell expression data that reflect the full heterogeneity of target exposure. This service is designed for biotech and pharma teams developing ADCs for breast cancer and other solid tumors, providing actionable data for patient stratification, dose optimization, and detection of resistance mechanisms. By linking target expression levels to ADC PK/PD outcomes, our approach helps de-risk clinical development and accelerate the path to regulatory submission.
Our workflow integrates CTC enrichment, fluorescence-based target quantification, and rigorous quality control to ensure reproducibility across time points and patient cohorts. The final report includes expression histograms, positivity thresholds, and correlation plots with clinical endpoints when available.
What We Offer
Quantitative Target Expression on CTCs
Measure ADC target density (e.g., TROP2, HER2, c-Met) on individual circulating tumor cells using validated immunofluorescence protocols. Output is expressed as mean fluorescence intensity (MFI) and percentage of target-positive CTCs, enabling both continuous and threshold-based analyses.
Multi-Target Panels & Custom Markers
Simultaneously assess up to four targets per sample to capture co-expression patterns and evaluate target competition. Custom marker panels can be developed for emerging ADC targets as needed, with initial validation in spiked cell models and control cell lines.
Integrated CTC Enumeration & Phenotyping
Combine target expression analysis with standard CTC enumeration (CellSearch or other platforms) and additional phenotypic markers (e.g., EpCAM, cytokeratin, CD45) to confirm CTC identity and exclude leukocyte contamination. This holistic view supports correlation with clinical outcomes and dynamic changes during treatment.
How It Works
We provide collection kits and detailed instructions for peripheral blood draw (7.5–10 mL) in CellSave tubes. Samples are shipped at ambient temperature and processed within 96 hours to preserve CTC integrity and target antigen stability.
CTCs are enriched using immunomagnetic separation targeting EpCAM or a broad tumor-associated antigen panel. Captured cells are identified by cytokeratin positivity, DAPI nuclear staining, and CD45 negativity, ensuring high specificity for epithelial-derived tumor cells.
Fluorescently labeled antibodies specific to the ADC target (e.g., anti-TROP2, anti-HER2) are applied to fixed CTCs. Image-based quantification is performed using automated scanning microscopy, measuring mean fluorescence intensity per cell and generating histograms of expression distribution.
Raw fluorescence data are normalized using isotype controls and standardized beads. The final report includes per-patient expression profiles, summary statistics (median MFI, % positive CTCs), and comparison to reference cell lines. Results are delivered in a secure online portal with raw data files available on request.
Deliverables
| Item | Description |
|---|---|
| Per-Cell Target Expression Data | Mean fluorescence intensity (MFI) for each CTC, with histograms and cumulative distribution plots. |
| Percentage of Target-Positive CTCs | Threshold-based positivity rate using a validated cutoff derived from negative controls. |
| CTC Enumeration & Phenotypic Profile | Total CTC count and subpopulation analysis (EpCAM+, cytokeratin+, CD45–) for sample quality assessment. |
| Comparative Expression Report | Expression levels across time points and patients, with optional comparison to matched tissue biopsy data (if provided). |
Key Differentiators
Real-Time Monitoring via Liquid Biopsy
Repeated blood draws allow longitudinal tracking of target expression without the need for invasive tissue biopsies, enabling dynamic assessment of target modulation, dose–response relationships, and early detection of antigen escape during ADC therapy.
Quantitative, Not Just Binary
Unlike standard immunohistochemistry that provides only categorical scores (0, 1+, 2+, 3+), our method delivers continuous MFI values per cell. This granularity supports more sensitive detection of expression shifts and better correlation with ADC internalization and cytotoxicity.
Broad Target Coverage & Customization
We offer validated assays for the most common ADC targets (TROP2, HER2, c-Met, EGFR, etc.) and can develop custom panels for novel antigens. Target validation includes confirmation of specificity on tumor cell lines and normal blood cells.
Integration with PK/PD and Resistance Studies
Our data can be combined with pharmacokinetic measurements and functional assays (e.g., bystander killing, payload release) to build a comprehensive pharmacodynamic picture. This supports go/no-go decisions and mechanistic understanding of resistance.
Featured Research
Research Highlight
Evaluation of Quantitative Relationship Between Target Expression and Antibody-Drug Conjugate Exposure Inside Cancer Cells
View articleAdvance Your ADC Pipeline
Contact our scientific team to discuss how our target expression analysis service can support your ADC development program, from target validation through clinical monitoring. We will tailor the assay panels, sample logistics, and reporting format to your specific program needs.