Extracellular Vesicle DNA Extraction and Sequencing in Ancient Serum Samples From Patients With Breast Cancer.

BACKGROUND/AIM: Extracellular vesicle DNA (EV-DNA) has emerged as a novel biomarker for tumor mutation detection using liquid biopsies, exhibiting biological advantages compared to cell-free DNA (cfDNA). This study assessed the feasibility of EV-DNA and cfDNA extraction and sequencing in old serum samples of patients with breast cancer (BC). PATIENTS AND METHODS: A total of 28 serum samples of 27 patients with corresponding clinical information were collected between 1983 and 1991. EV-DNA was extracted using Exo-GAG kit (Nasabiotech) and cfDNA using QIAsymphony DSP Virus/Pathogen Midi Kit (Qiagen), respectively. Subsequently, 10 matched samples (EV-DNA n=5, cfDNA n=5) of five patients were subjected to sequencing using the Oncomine™ Breast cfDNA Research Assay v2 (Thermo Fisher Scientific). RESULTS: Samples were collected on median 1.9 years after primary diagnosis [interquartile range (IQR)=0.2-7.2]. Median follow-up was 9.5 years (IQR=5.2-14.2). Median age of serum samples was 36.1 years (IQR=34.5-37.3). EV-DNA and cfDNA were extracted from 100% (28/28) of the included samples. Both, DNA quantity and concentration were comparable between EV-DNA and cfDNA. Sequencing was successfully performed in 100% (10/10) of the included samples. Two matched analyses yielded equivalent results in EV-DNA and cfDNA (no mutations, n=1; PIK3CA mutation, n=1), whilst in two analyses, PIK3CA mutation was only found in cfDNA, and in one analysis, a TP53 mutation was only found in EV-DNA. CONCLUSION: EV-DNA extraction and sequencing in old serum samples of patients with BC is feasible and has the potential to address clinically relevant questions in longitudinal studies.

Single-incision for breast-conserving surgery through round block technique.

AIMS AND OBJECTIVES: The purpose of this study was to assess the feasibility of using the single-incision round block technique in breast-conserving surgery with sentinel lymph node (SLN) retrieval for breast cancer without compromising oncological safety. MATERIALS AND METHODS: A retrospective observational case-control study was conducted from January 2017 to October 2021. The study population consisted of two groups. In both groups, breast-conserving surgery was carried out through the round-block technique. In group A, SLN retrieval was performed using the round-block incision (study group), while in group B, SLN retrieval was conducted through a second skin incision in the axilla (control group). The study was approved by the local ethics committee Zurich (BASEC-Nr. 2020-02857), and written informed consent was obtained from all participants. RESULTS: Overall, 134 patients met the inclusion criteria, of whom 86 women underwent breast-conserving surgery and SLN retrieval using the single-incision approach (group A), and 48 women underwent conventional surgery, using two independent incisions for tumour resection and SLN retrieval (group B). The overall success rate in group A regarding SLN retrieval was 97.7%, whereas most tumours were located in the upper outer (47.7%) and upper inner quadrant (27.9%). Although the technique was equally successful in the other quadrants, the share of tumours in the lower outer, and the lower inner quadrant, and the retroareolar region was smaller, representing 17.4%, 3.5% and 3.5%, respectively. The median number of dissected lymph nodes was two, with a positivity rate of 24.4%. The occurrence of axillary neuralgia and axillary skin retraction was significantly higher in group B along with tendentially more axillary seroma formation. There were no significant differences regarding reintervention rates, in terms of complications, resection margins, locoregional recurrences, or deaths with a mean follow-up of 11 months. CONCLUSIONS: The single-incision method through the round block technique is as safe and effective as the standard two-incision approach regarding nodal staging and resection margins, and seems to be applicable for tumours in all breast quadrants.