Plasma circulating tumor DNA as a genomic biomarker for ovarian cancer

Abstract

Introduction
Ovarian cancer (OC) remains the most lethal disease among gynecological malignancies as most patients are diagnosed in an advanced stage. Circulating tumor DNA (ctDNA) liquid biopsy analysis holds promise as a minimally-invasive multipurpose biomarker. In this pilot study, we investigate ctDNA monitoring in OC.
Material and Methods
Twelve OC patients from Keio Women’s Health Biobank at Keio University School of Medicine were studied: the histological subtypes comprised eight serous, two clear cell, one mucinous and one endometrioid. Diagnostic tumor and serial peripheral blood samples were collected. Following identification of tumor mutations, we performed quantitative detection of ctDNA in plasma from various timepoints using the ultrasensitive IBSAFE method.
Results
Concordant mutations in tumor DNA and plasma DNA were detected in eleven patients (91%); only one mutation in a non-recurrent patient was undetectable in plasma. Among the five recurrent patients, all patients detected positive ctDNA prior to or simultaneously to CT imaging. Positive ctDNA was detected earlier than high CA125 in 3/5 patients with a median of 86 days. ctDNA also had sensitive reaction to tumor burden during chemotherapy. ctDNA from all seven non-recurrent patients turned negative after initial treatment and maintained negative throughout the follow-up.
Conclusions
Detection of plasma ctDNA was feasible. ctDNA has the potential of enhancing presence diagnosis by shortening the lead time than CA125 or CT imaging. ctDNA may be a clinically useful biomarker for OC patients.

Christian Brueffer

Bioinformatician and Data Scientist

Freelance Bioinformatician and Data Scientist with interests including disease biology and diagnostics, particularly in cancer, and open source bioinformatics.