Predictive Factors for CNS Metastases in Early Breast Cancer Using Liquid Biopsy (AKRA CŽS) (AKRA CŽS)

Predictive Factors in Primary Tumor and Liquid Biopsy for the Spread of Early Breast Cancer to the Central Nervous System

Breast cancer is the most common cancer in women. Although most patients are diagnosed at an early stage and treated with curative intent, some later develop metastases to the central nervous system (CNS), which are associated with poor prognosis and high morbidity. Currently, there are no validated biomarkers that reliably predict which patients with early-stage breast cancer are at increased risk for CNS metastases.

This study aims to identify molecular predictors of CNS metastases in early breast cancer. Gene expression profiles (mRNA) from archived primary tumor tissue will be analyzed using next-generation sequencing (NGS). In addition, serum concentrations of chemokines CX3CL1, CXCL13, and CXCL8 (IL-8), measured at the time of diagnosis using ELISA, will be evaluated for their association with subsequent CNS metastases.

The results may improve risk stratification and support earlier identification of patients at increased risk for CNS spread.

Study Overview

• Status: Active, not recruiting
• Conditions: Breast Cancer; Central Nervous System Metastases
• Intervention / Treatment: Diagnostic test: Primary Tumor mRNA Expression Profiling (NGS); Diagnostic test: Serum Chemokine Quantification (ELISA)

Detailed Description

Breast cancer is frequently diagnosed at an early stage. Despite appropriate curative treatment, a subset of patients develops distant metastases during follow-up. Metastases to the central nervous system (CNS) represent a serious clinical complication due to their significant impact on morbidity and mortality. At present, no validated blood-based biomarkers are available to reliably predict CNS dissemination in patients with early-stage breast cancer.

The primary objective of this study is to identify genes that are differentially expressed in archived primary breast tumor tissue of patients who subsequently developed CNS metastases compared with matched controls who did not develop CNS metastases. Gene expression will be assessed using next-generation sequencing (NGS) of cDNA derived from mRNA.

The secondary objective is to evaluate whether baseline serum concentrations of chemokines CX3CL1, CXCL13, and CXCL8 (IL-8), measured using enzyme-linked immunosorbent assay (ELISA), are associated with the later development of CNS metastases.

The study includes two clinically comparable groups of patients with early-stage breast cancer:

patients who developed CNS metastases during follow-up, and

matched control patients without CNS metastases.

Statistical analyses will include descriptive statistics, univariate and multivariate logistic regression models, and receiver operating characteristic (ROC) curve analysis to evaluate predictive performance of the investigated biomarkers.

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Slovenia
  • Ljubljana, Slovenia, 1000
    • Institute of Oncology Ljubljana

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Female patients aged 18 years or older.
• Diagnosis of early-stage breast cancer.
• Availability of archived primary tumor tissue suitable for mRNA analysis.
• Availability of serum sample suitable for chemokine analysis.
• Patients included in the AKRA cohort with documented follow-up data.
• Patients with confirmed CNS metastases during follow-up (CNS metastases group) or matched controls without CNS metastases (control group).

Exclusion Criteria:

• Male breast cancer patients.
• Lack of sufficient primary tumor tissue for mRNA analysis.
• Lack of available serum sample for chemokine analysis.
• Incomplete clinical follow-up data preventing classification of CNS metastasis status.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: CNS Metastases Group; Female patients with early-stage breast cancer who developed central nervous system (CNS) metastases during follow-up. Participants undergo molecular biomarker assessment consisting of primary tumor mRNA gene expression profiling using next-generation sequencing (NGS) and measurement of baseline serum chemokine concentrations (CX3CL1, CXCL13, CXCL8 [IL-8]) using ELISA.	Diagnostic test: Primary Tumor mRNA Expression Profiling (NGS); Gene expression profiling of mRNA derived from archived primary breast tumor tissue using next-generation sequencing (NGS) to identify genes differentially expressed between patients who developed CNS metastases and matched controls.; Diagnostic test: Serum Chemokine Quantification (ELISA); Measurement of serum concentrations of chemokines CX3CL1, CXCL13, and CXCL8 (IL-8) collected at diagnosis using enzyme-linked immunosorbent assay (ELISA) to evaluate their association with subsequent CNS metastases.
Active Comparator: Control Group (No CNS Metastases); Matched female patients with early-stage breast cancer who did not develop CNS metastases during follow-up. Participants undergo molecular biomarker assessment consisting of primary tumor mRNA gene expression profiling using next-generation sequencing (NGS) and measurement of baseline serum chemokine concentrations (CX3CL1, CXCL13, CXCL8 [IL-8]) using ELISA.	Diagnostic test: Primary Tumor mRNA Expression Profiling (NGS); Gene expression profiling of mRNA derived from archived primary breast tumor tissue using next-generation sequencing (NGS) to identify genes differentially expressed between patients who developed CNS metastases and matched controls.; Diagnostic test: Serum Chemokine Quantification (ELISA); Measurement of serum concentrations of chemokines CX3CL1, CXCL13, and CXCL8 (IL-8) collected at diagnosis using enzyme-linked immunosorbent assay (ELISA) to evaluate their association with subsequent CNS metastases.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Differential Gene Expression in Primary Tumor Tissue Associated With CNS Metastases	Identification of genes differentially expressed in primary breast tumor tissue between patients who developed CNS metastases and matched controls without CNS metastases, assessed by mRNA expression profiling using NGS.	Up to 36 months after baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Association Between Baseline Serum Chemokine Concentrations and CNS Metastases	Assessment of serum concentrations of CX3CL1, CXCL13, and CXCL8 (IL-8) measured at diagnosis using ELISA and their association with subsequent development of CNS metastases during follow-up.	Up to 36 months after baseline

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Predictive Performance of Combined Molecular Biomarker Model for CNS Metastases (ROC Analysis)	Evaluation of predictive accuracy of combined molecular biomarkers (mRNA expression profiles and serum chemokine concentrations) together with clinical-pathological variables using ROC curve analysis.	Up to 36 months after baseline

Collaborators and Investigators

• Sponsor: Institute of Oncology Ljubljana

Study record dates

Study Major Dates

• Study Start (Actual): July 7, 2025
• Primary Completion (Actual): December 31, 2025
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: February 19, 2026
• First Submitted That Met QC Criteria: February 26, 2026
• First Posted (Actual): March 3, 2026

Study Record Updates

• Last Update Posted (Actual): March 3, 2026
• Last Update Submitted That Met QC Criteria: February 26, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: early-stage breast cancer; molecular biomarkers
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: OI-AKRA-CNS-2025; 0120-315/2025-2711-3 (Other Identifier: Clinical Research Unit, Institute of Oncology Ljubljana)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No