We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress
Sign In
Advertise with Us
PURITAN MEDICAL

Download Mobile App




Events

09 Apr 2024 - 12 Apr 2024
15 Apr 2024 - 17 Apr 2024
23 Apr 2024 - 26 Apr 2024

Molecular Test Developed for Nasopharyngeal Carcinoma

By LabMedica International staff writers
Posted on 12 Jun 2018
Print article
Image: The NextSeq 500 desktop sequencing platform (Photo courtesy of Illumina).
Image: The NextSeq 500 desktop sequencing platform (Photo courtesy of Illumina).
The prevalence of nasopharyngeal carcinoma (NPC) is higher in Southeast Asia than other parts of the world, around 35 cases per 100,000. Five-year survival rate of the disease is as high as 95% when it is detected early, but drops to 60% if detected at later stage. Most patients are asymptomatic, and so 80% are diagnosed with advanced disease.

Liquid biopsies via circulating cell-free DNA (cfDNA) analysis have been shown to be of value in noninvasive monitoring of cancer treatment response and for the detection of cancer recurrence. To extend the application of circulating cell-free DNA to cancer screening, investigators have to face the challenge of developing assays that are sufficiently sensitive for detecting the expectedly low concentrations of circulating tumor DNA in early stages of cancer.

Scientists at The Chinese University of Hong Kong (Sha Tin, Hong Kong) analyzed a target population that was asymptomatic, ethnically Chinese males aged between 40 and 62 years. This group has the highest age-specific incidence of NPC. All of the participants provided a venous blood sample of 20 mL at enrollment. The team used 800 mL of plasma for Epstein - Barr virus (EBV) DNA analysis by a real-time polymerase chain reaction (RT-PCR) assay, which targeted the BamH1-W fragment of the EBV genome.

For enrichment of viral DNA molecules from the plasma DNA samples for subsequent sequencing analysis, target enrichment with EBV capture probes was performed. DNA libraries from five samples were multiplexed in one capture reaction. Equal amounts of DNA libraries for each sample were used. The team also included probes to cover human autosomal regions for reference. The captured autosomal DNA sequences were used for normalization of the viral DNA reads. The multiplexed DNA libraries were sequenced using either the NextSeq 500 or the HiSeq 2500 Sequencing platforms.

The team used a targeted sequencing approach to target the Epstein Barr virus, generating around 70 million mapped reads per sample. Sequencing confirmed that those with cancer had a higher proportion of viral DNA than those without. In addition, they found size differences between the viral DNA in individuals with and without cancer. The circulating DNA has an average size of around 160 to 170 bases because a piece of DNA wrapped around a histone core is around 140 bases, with another 20-base linker region. In the previous liver cancer study, the team demonstrated that circulating DNA (ctDNA) did not have that 20-base linker region. By contrast, viral DNA in cancer-free individuals had not integrated into the genome.

Overall, when they combined the count-based analysis to determine the concentration of viral DNA and the sized-based analysis, the targeted sequencing test had a sensitivity of 97.1%, a specificity of 99.3%, and a PPV of 19.6% an improvement over the PCR assay which had a PPV of 11% and required sampling at two time points. The PCR assay when used at a single time point had a PPV of just 3.1%. However, one advantage of a PCR-based approach is its low cost. In a previous study, for instance, the investigates reported that the cost of testing was just USD 30, as compared to USD 80 and USD 1,000 for endoscopic tests and MRI, respectively. The study was published on May 14, 2018, in the journal Proceedings of the National Academy of the Sciences.

Related Links:
The Chinese University of Hong Kong

Platinum Member
COVID-19 Rapid Test
OSOM COVID-19 Antigen Rapid Test
One Step HbA1c Measuring System
GREENCARE A1c
POCT Fluorescent Immunoassay Analyzer
FIA Go
New
Gold Member
Fully Automated Cell Density/Viability Analyzer
BioProfile FAST CDV

Print article

Channels

Clinical Chemistry

view channel
Image: Reaching speeds up to 6,000 RPM, this centrifuge forms the basis for a new type of inexpensive, POC biomedical test (Photo courtesy of Duke University)

POC Biomedical Test Spins Water Droplet Using Sound Waves for Cancer Detection

Exosomes, tiny cellular bioparticles carrying a specific set of proteins, lipids, and genetic materials, play a crucial role in cell communication and hold promise for non-invasive diagnostics.... Read more

Hematology

view channel
Image: The low-cost portable device rapidly identifies chemotherapy patients at risk of sepsis (Photo courtesy of 52North Health)

POC Finger-Prick Blood Test Determines Risk of Neutropenic Sepsis in Patients Undergoing Chemotherapy

Neutropenia, a decrease in neutrophils (a type of white blood cell crucial for fighting infections), is a frequent side effect of certain cancer treatments. This condition elevates the risk of infections,... Read more

Pathology

view channel
Image: The OvaCis Rapid Test discriminates benign from malignant epithelial ovarian cysts (Photo courtesy of INEX)

Intra-Operative POC Device Distinguishes Between Benign and Malignant Ovarian Cysts within 15 Minutes

Ovarian cysts represent a significant health issue for women globally, with up to 10% experiencing this condition at some point in their lives. These cysts form when fluid collects within a thin membrane... Read more
Copyright © 2000-2024 Globetech Media. All rights reserved.