Feasibility of PIK3CA Mutation Detection via Microfluidic Isolation of Disseminated Tumor Cells from Bone Marrow in Breast Cancer Patients

Abstract

Disseminated tumor cells originating from the bone marrow serve as precursors of distant metastasis and are associated with increased mortality in breast cancer. With the emergence of targeted therapies for breast cancer, accurate procedures for enrichment of disseminated tumor cells are crucial to investigate the molecular heterogeneity between disseminated tumor cells and primary tumors. This study evaluated the feasibility of PIK3CA mutation analysis in disseminated tumor cells enriched using a microfluidic-based separation system.
Bone marrow and primary tumor samples from 84 breast cancer patients were collected. Disseminated tumor cells were enriched from bone marrow aspirates using the Parsortix system, followed by PIK3CA mutation analysis via MassARRAY PIK3CA Breast Panel and digital droplet PCR.
PIK3CA mutations were detected in 42.9% of primary tumors. PIK3CA mutations were neither detected via digital droplet PCR in disseminated tumor cells-positive bone marrow samples, nor in disseminated tumor cells-negative samples with a high allele frequency of PIK3CA mutations in the primary tumor.
These findings suggest that current microfluidic enrichment methods, such as Parsortix, may be insufficient for reliable PIK3CA mutation detection in disseminated tumor cells. Additional research is required to investigate alternative enrichment techniques for the analysis of mutations in disseminated tumor cells.

Zusammenfassung

Aus dem Knochenmark stammende disseminierte Tumorzellen dienen als Vorläufer von Fernmetastasen und stehen in Zusammenhang mit einer erhöhten Mortalität bei Brustkrebs. Mit dem Entstehen gezielter Therapien für Brustkrebs sind neue Verfahren zur Anreicherung disseminierter Tumorzellen von entscheidender Bedeutung, um die molekulare Heterogenität zwischen disseminierten Tumorzellen und Primärtumoren zu untersuchen. In dieser Studie wurde die Durchführbarkeit der PIK3CA-Mutationsanalyse von disseminierten Tumorzellen getestet, die zuvor mithilfe eines mikrofluiden Systems angereichert wurden, überprüft.
Es wurden Knochenmark- und Primärtumorproben von 84 Brustkrebspatientinnen entnommen. Die disseminierten Tumorzellen wurden aus Knochenmarkaspiraten mit dem Parsortix-System angereichert, gefolgt von einer PIK3CA-Mutationsanalyse mittels MassARRAY PIK3CA Breast Panel und Digital Droplet-PCR.
PIK3CA-Mutationen wurden in 42,9% der Primärtumoren nachgewiesen. PIK3CA-Mutationen wurden weder mittels Digital Droplet-PCR in disseminierten tumorzellpositiven Knochenmarkproben noch in disseminierten tumorzellnegativen Proben mit einer hohen Allelfrequenz von PIK3CA-Mutationen im Primärtumor nachgewiesen.
Diese Ergebnisse deuten darauf hin, dass aktuelle mikrofluide Anreicherungsmethoden wie Parsortix möglicherweise keinen zuverlässigen Nachweis von PIK3CA-Mutationen in disseminierten Tumorzellen ermöglichen. Es sind weitere Studien erforderlich, um alternative Anreicherungsverfahren für die Mutationsanalyse in disseminierten Tumorzellen zu erforschen.

Keywords

Parsortix - disseminated tumor cells (DTCs) - breast cancer - liquid biopsy - digital droplet PCR (ddPCR)

Schlüsselwörter

Parsortix - disseminierte Tumorzellen (DTCs) - Brustkrebs - Liquid Biopsy - Digital Droplet-PCR (ddPCR)

Publication History

Received: 27 August 2025

Accepted after revision: 22 November 2025

Article published online:
13 January 2026

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