Multiplex IHF TLS detection & scoring for oncology clinical trials
Explicyte provides an analytically validated multiplex IHF assay for TLS detection and maturity scoring in FFPE tumor samples from oncology clinical trials.
Our pathologist-led service delivers standardized TLS classification and study-ready reporting within our ISO 13485 and ISO 9001-certified quality-management framework.
Experts in TLS evaluation
Applying TLS scoring workflows in peer-reviewed studies since 2021
Fc-optimized CD40 agonistic antibody elicits tertiary lymphoid structure formation and systemic antitumor immunity in metastatic cancer
Reshaping the tumor microenvironment of cold soft-tissue sarcomas with anti-angiogenics: a phase 2 trial of regorafenib combined with avelumab
Spatially resolved transcriptomics reveal the determinants of primary resistance to immunotherapy in NSCLC with mature tertiary lymphoid structures
Tertiary lymphoid structures and cancer immunotherapy: From bench to bedside
Deciphering the correlation between metabolic activity through 18F-FDG-PET/CT and immune landscape in soft-tissue sarcomas: an insight from the NEOSARCOMICS study
Upregulation of Indoleamine 2,3-Dioxygenase 1 in Tumor Cells and Tertiary Lymphoid Structures is a Hallmark of Inflamed Non–Small Cell Lung Cancer
Standardized Pathology Screening of Mature Tertiary Lymphoid Structures in Cancers
Pembrolizumab combined with low-dose cyclophosphamide and intra-tumoral injection of the toll-like receptor 4 agonist G100 in patients with advanced pretreated soft tissue sarcoma: results from the PEMBROSARC basket study
Pembrolizumab in soft-tissue sarcomas with tertiary lymphoid structures: a phase 2 PEMBROSARC trial cohort
Mature tertiary lymphoid structures predict immune checkpoint inhibitor efficacy in solid tumors independently of PD-L1 expression
TLS ASSAY SPECIFICATIONS
A validated TLS assay for oncology clinical trials
Explicyte is ISO 13485:2016 and ISO 9001:2015 certified by Euro-Quality System (certificates 260133/1637F/1 and 260133/1637F/2). The TLS scoring assay is the first biomarker assay developed under this certified QMS, whose scope includes the design and development of tissue biomarkers and tissue-biomarker testing for precision-oncology clinical trials. Assay methods, controls, acceptance criteria, scoring procedures and study records are managed through controlled documentation.
Certification applies to the quality-management system and its defined scope; it does not, by itself, make the TLS assay a CE-marked IVD or companion diagnostic.
How TLS status is classified
Scoring TLS status and spatial distribution in tumor tissue
TLS status is assigned by trained pathologists using the CD3/CD8/CD20/CD23/CD163/PanCK multiplex IHF panel together with a serial HES (hematoxylin–eosin–saffron) section. Mature TLS are defined by the presence of CD23-positive follicular dendritic-cells (FDCs), either as isolated (n-fmTLS) or organized into a network (fmTLS), whereas immature TLS lack these maturation features.
Representative images from the published TLS research workflow.
The current commercial assay uses the updated panel described above.
Download a sample TLS assay report
See exactly what you receive: per-case TLS status, spatial location, representative images and cohort-level summary.
TLS ASSAY WORKFLOW
From FFPE tumor tissue to a pathologist-reviewed TLS result
A controlled pathology workflow from sample receipt through staining, imaging, TLS classification and study reporting.
Sample intake & pathology QC
Confirm tissue suitability and prepare serial sections
FFPE tumor blocks or unstained slides are registered, assessed for suitability and processed according to the study plan. When blocks are provided, serial sections are prepared for HES staining and multiplex IHF.
Key outputs
- Controlled specimen accession and traceability
- Pathology suitability review
- Serial sections prepared according to the assay workflow
ASSAY EXECUTION
Generate HES morphology and multiplex IHF readouts
HES and CD3/CD8/CD20/CD23/CD163/PanCK multiplex IF are performed according to the controlled assay method, with automated staining, multispectral imaging and defined run-level controls.
Key outputs
- Assay image set supporting TLS classification
- Run-level QC and control records
- Case material prepared for standardized interpretation
Pathologist interpretation & reporting
Classify TLS status using the validated scoring framework
Trained pathologists integrate morphology from HES-stained sections and multiplex IF findings to assign TLS status and location according to the controlled assay method. Results are reported per case, with cohort-level summaries available when required by the study.
Key outputs
- Per-case TLS status
- Representative supporting images
- Cohort-level summary when requested
CLINICAL EVIDENCE
From pan-cancer association to prospective clinical evaluation
Explicyte-supported studies have linked mature TLS with response and survival under immune-checkpoint blockade across solid tumors and prospectively evaluated TLS-based enrichment in a phase 2 sarcoma cohort.
NEED A DIFFERENT TISSUE BIOMARKER ASSAY?
Develop and validate a custom IHC/IF assay for your trial
Explicyte develops and analytically validates custom IHC and multiplex IF tissue biomarker assays, from assay optimization through controlled clinical-trial deployment.
Paul Marteau, PharmD (study director), Imane Nafia, PhD (CSO), Loïc Cerf, MSc (COO), Alban Bessede, PhD (founder, CEO), Jean-Philippe Guégan, PhD (CTO)
Contact our team
Discuss TLS scoring for your clinical study
Tell us the indication, trial phase, tissue type, number of cases, available FFPE material, planned study timepoints and how TLS status will be used in the protocol. We’ll confirm sample requirements, reporting format, study workflow and timeline.
Frequently asked questions
Answers about TLS scoring
What samples can be analyzed with the TLS scoring assay?
The assay is designed for FFPE tumor tissue. Sponsors can provide FFPE blocks or unstained slides, with tissue and section requirements confirmed before study initiation. A pathology suitability review is performed before scoring to identify samples that may not provide sufficient evaluable tissue.
What result do I receive for each case?
Each evaluable case receives a standardized TLS classification — TLS-negative, immature TLS or mature TLS — together with the spatial location of identified TLS and representative supporting images. Cohort-level summaries can also be provided when required by the study design.
How is TLS maturity determined?
TLS status is determined by trained pathologists using tissue morphology from a serial HES (hematoxylin–eosin–saffron)-stained section together with the current CD3/CD8/CD20/CD23/CD163/PanCK multiplex IHF panel. Mature TLS are identified by CD23-positive follicular dendritic cells, either isolated or organized into a follicular network, whereas immature TLS lack these maturation features. Earlier Explicyte-supported publications used a CD4/CD8/CD20/CD21/CD23 multiplex IF workflow; the current clinical-study assay is an updated implementation performed according to its controlled scoring method.
Can TLS scoring be used for patient stratification or selection in an oncology trial?
TLS status can be incorporated into a clinical-study biomarker strategy when supported by the protocol and development plan. Published studies have associated mature TLS with improved outcomes under immune-checkpoint blockade, and TLS-based enrichment was prospectively evaluated in the PEMBROSARC phase 2 cohort. The Explicyte assay is not, by itself, a CE-marked IVD or approved companion diagnostic; any formal patient-selection or regulated diagnostic strategy should be defined with the sponsor.
Can core biopsies be evaluated as well as surgical specimens?
FFPE biopsies and resection specimens can be considered, provided sufficient evaluable tumor tissue is available. Because TLS are spatially heterogeneous structures, tissue amount and sampling context can affect their detection; sample adequacy and study design should therefore be reviewed before testing, particularly for small biopsies.
What turnaround should we plan for?
Turnaround depends on cohort size, sample format, tissue quality and reporting requirements. Share the number and type of samples with us and we will define the study schedule before initiation.
How does the validated assay relate to the published TLS studies?
The current assay builds on the TLS classification strategy used in Explicyte-supported publications, which employed a CD4/CD8/CD20/CD21/CD23 multiplex IF workflow. The clinical-study assay uses an updated CD3/CD8/CD20/CD23/CD163/PanCK multiplex IHF panel together with a serial HES section and has been analytically validated for repeatability, reproducibility, scoring consistency and robustness under its intended-use conditions. It is implemented within Explicyte’s ISO-certified quality-management framework.
