Nasopharyngeal swab and pcr for the screening of nasopharyngeal carcinoma in the endemic area: A good supplement to the serologic screening

Abstract

Background Nasopharyngeal carcinoma (NPC) is a common head and neck cancer in Taiwan. Early detection is the best way to improve survival for this disease. A prospective study was designed to assess the feasibility of a new screening method for NPC by use of polymerase chain reaction (PCR) based on the close association of NPC and Epstein‐Barr virus (EBV). Methods One hundred thirty‐three different tissues from nasopharynx, nose, and sinus were investigated by use of PCR to check for the presence of EBV genome. Subsequently, from April 1996 to March 1997, 55 patients were enrolled in a prospective screening study. All patients underwent nasopharyngeal swabs before biopsy. Polymerase chain reaction detection of EBV genome was conducted on swab samples. Anti‐EBV viral capsid antigen (VCA) in IgA and IgG class were checked at the same visit. Results The EBV genome was present in 91.4% (85/93) of NPC tissues and in 25.0% (10/40) of non‐NPC tissues (p< .001, χ2 test). Of the 55 swabs, 49 (89.1%) specimens obtained enough cells for PCR examination. Thirty of these 49 patients were pathologically proved NPC. The presence of EBV were 86.7% (26/30) in NPC group and 42.1% (8/19) in non‐NPC group. The sensitivity and specificity were 86.7% and 57.9%, respectively, which were similar to those of serologic method (87.5% and 43.5%) when the cut‐off point was set at anti‐VCA IgG ≥ 160 and IgA ≥ 10. Combining both methods elevates the specificity to 84.2%. Conclusions The sensitivity of this PCR screening method is similar to that of the serologic method. Combining both methods can greatly increase the specificity, indicating this new method is a good supplement to the serologic screening of this endemic disease. © 1998 John Wiley & Sons, Inc. Head Neck 20: 732–738, 1998.

Noninvasive diagnosis of nasopharyngeal carcinoma: Nasopharyngeal brushings reveal high Epstein‐Barr virus DNA load and carcinoma‐specific viral BARF1 mRNA

“…24,26 This may be because of insensitive, qualitative (multiplex) PCR assays 24 or insufficient brushing of the NP epithelium in these controls. In contrast, several other studies 25,45 and our present study using sensitive quantitative real-time PCR, have found EBV DNA in brushing specimens from most healthy carriers, albeit at low levels. This is not surprising, as EBV-infected B-lymphocytes have a homing preference for the NP region (Waldeyer's ring) and virus is shed into the oropharyngeal space.…”

Presence of the latent membrane protein 1 gene in nasopharyngeal swabs from patients with mucosal recurrent nasopharyngeal carcinoma

“…Sheen et al also demonstrated that nasopharyngeal swabbing and PCR could supplement serologic screening effectively in newly diagnosed NPC. 20 In addition, Sheen et al reported a 77.8% positive LMP-1 rate in the recurrent group and a 0.0% positive LMP-1 rate in the control group; however, the number of patients in their study was limited. The current investigation is the largest study to date emphasizing the relation between local recurrence in patients who were treated with definitive radiotherapy and re-LMP-1.…”

“…26 Nevertheless, some reports have revealed that the LMP-1 genome could be identified at a rate of 25-80% from throat washings, nasopharyngeal biopsies, or swabs in individuals without NPC or apparent EBV-related disease. 20 Along with the possibility that cross-contamination during tissue sampling or PCR may be able to explain the divergence in the detection of the EBV genome in the nasopharynx, more effort should be made to clarify whether the divergence in the probability of detecting EBV specific genomic DNA is a consequence of crosscontamination or a more sensitive and specific assay, such as nest PCR. 27 In any event, the current study tested EBNA in patients who had two successive positive results for re-LMP-1 to minimize the possibility of cross-contamination.…”

Epstein-Barr Virus DNA Load in Nasopharyngeal Brushings and Whole Blood in Nasopharyngeal Carcinoma Patients before and after Treatment

“…Previous studies revealed nasopharyngeal brushing as a simple procedure with minor discomfort, being well tolerated and reflecting carcinoma-specific EBV involvement at the anatomical site of tumor development, thereby reducing the need for invasive biopsies (12)(13)(14). This procedure has promise as confirmation test in serological NPC screening programs and has potential as prognostic tool for therapy assessment and follow-up monitoring.…”