NP Screen™ is a quantitative PCR genetic test for the detection of Epstein Barr Virus DNA, which correlates with a high degree of sensitivity and specificity for the presence of Nasopharyngeal Carcinoma.
A specially designed test kit containing a trans-oral brush and preserving solution is used to retrieve cells from the Nasopharynx for DNA collection, preservation and analyses. NP Screen™ was developed as a Laboratory Developed Test (LDT) and the results were validated by Primex Clinical Laboratory which is regulated under the Clinical Laboratory Improvement Amendments of 1988 (“CLIA”) as qualified to perform high complexity clinical testing.
Step 1: Brush
• First group to utilize trans-oral approach to brush nasopharynx
• Specially designed angled brush to enter the nasopharynx
• Nasopharynx brushing collects fresh epithelial/pre-neoplastic/tumor cells
• Brushing technique is simple, easy to learn for healthcare professionals
• Non-invasive, well tolerated by patients
Step 2: Ship
• After brushing and cell collection, sample is deposited in vial with preservation solution, allowing genetic material to be stored easily
• Proven to permit a minimum of 30 days DNA stability and preserving capability
• Process allows sample collection and screening in remote locations
Step 3: Results
• Quantitative Polymerase Chain Reaction (PCR) technology
• Determination of the presence and quantity of EBV DNA in the brushed NP epithelial cells
• Correlation between the EBV DNA detection levels with the presence or absence of NPC
• Confirmed by biopsy and pathologic diagnosis
• Brushing process needs only 50-100 cells, genetic material within the sample is then amplified using PCR
• Allows the screening test to detect sub-mucosal lesions, small lesions, and even pre-neoplastic lesions
• Detection of non-visible tumors is possible, even ones undetectable by endoscopy
• The distribution patterns of Epstein Barr Virus DNA Detection Level (EDL) values for brushed nasopharyngeal carcinoma (NPC) tumor and normal subjects.
The sample preservation system and associated protocol will provide a simple, routine, large-scale screening method for individuals at risk of developing NPC globally.
Summary of Clinical Studies
Double blinded clinical studies were conducted at referral clinics in Chinese communities in Toronto and Hong Kong. Chinese patients over 20 years of age (n=438, 37% female avg. age 52 years, 63% male avg. age 52 years) not previously treated for NPC were enrolled in the studies. A sample was collected from each patient using the NP Screen™ trans-oral swab which was then dispatched via common courier to the laboratories, Inc. for real-time PCR analysis using proprietary chemistries specifically designed and optimized to detect NPC markers. After sample collection, the post-nasal space was visualized using fiberoptic nasopharyngoscope and rated by an experienced ENT surgeon/Otolaryngologist and patients with suspicious findings were referred for biopsy and histopathologic evaluation. Patients whose biopsy was negative or who presented no clinical suspicions for NPC were classified as normal. The results of the clinical trials showed that the NP Screen™ assay screening results closely correlated with the final clinical diagnosis of the patient. The clinical sensitivity for NP Screen™ (i.e. the probability the test is positive when the disease is present) =98.8% and the clinical specificity for NP Screen™ (i.e. the probability the test is negative when the disease is not present)=100%. These results demonstrate the utility of NP Screen™ as an effective screen for NPC (Table 1).
Table 1, Screening Performance, NP Screen™ Result Compared to Final Clinical Status of Patient
|TP||FN||TN||FP||Clinical Sensitivity||Clinical Specificity|
The distribution of Epstein-Barr virus detection Levels (EDL) results and their correlation with the clinical diagnosis for the patient is presented in, Figure 1, and illustrates the potential for the NP Screen™ assay to predict NPC.
Figure 1, distribution of non-zero EDL values for normal and abnormal sub-groups.
The NPS400.00 specimen collection kit, laboratory reagents, laboratory equipment, procedures and controls are appropriate for the collection, transport and analysis to detect EBV DNA. The detection of EBV DNA is predictive of nasopharyngeal carcinoma and can serve as a screening tool. A positive screening result may guide the clinician in the diagnostic workup of occult primaries. DNA samples from 352 of 352 healthy patients (control patients) were non-reactive during PCR analysis indicating NP Screen™ assay is also an excellent tool for ruling out NPC.
Benefits of NP Screen™
• Highly accurate, sensitive and specific for detection of NPC
• Detects NPC in patients with sub-mucosal or inconspicuous lesions
• Helps identify local reoccurrences in post radiated patients
• Non-invasive, painless and highly tolerable
• Rapid out-patient and ambulatory procedure with negligible risk
• No equipment dependency
• Efficient result reporting
• Avoids patient suffering from enduring unnecessary pain and trauma by receiving treatments due to uncertain and false positive biopsy
• Avoids error and deviation of biopsy forceps not reaching deep enough