Screening nasopharyngeal carcinoma by detection of the latent membrane protein 1 (LMP-1) gene with nasopharyngeal swabs.
BACKGROUND
Nasopharyngeal carcinoma (NPC) is a common head and neck cancer in Taiwan. The goals of the current study were to investigate whether a nasopharyngeal swab technique could provide enough DNA for polymerase chain reaction (PCR) analysis of the Epstein-Barr virus (EBV)-derived latent membrane protein 1 (LMP-1) gene and to determine the feasibility and reliability of diagnosing NPC by detection of LMP-1 in the nasopharynx.


METHODS
320 adults underwent nasopharyngoscopy and nasopharyngeal swab to obtain cells for the LMP-1 PCR assay; some patients also underwent nasopharyngeal biopsy.


RESULTS
An amount of DNA that was sufficient for PCR was extracted from 96.3% of the swab samples. By detecting LMP-1 in nasopharyngeal swabs, NPC was diagnosed with a false positive rate of 12.7% (7 of 55 patients), a false negative rate of 1.6% (4 of 253 patients), sensitivity of 87.3% (48 of 55 patients), specificity of 98.4% (249 of 253 patients), a positive predictive value of 92.3% (48 of 52 patients), and a negative predictive value of 97.3% (249/256 patients). NPC was diagnosed by nasopharyngoscopy with a false positive rate of 38% (30 of 79 patients), a false negative rate of 0.4% (1 of 241 patients), sensitivity of 62% (49 of 79 patients), specificity of 99.6% (240 of 241 patients), a positive predictive value of 98% (49 of 50 patients), and a negative predictive value of 88.9% (240 of 270 patients). Only 7 (0.2%) of 256 patients with a diagnosis other than NPC had LMP-1 detected in the nasopharyngeal space.


CONCLUSIONS
Detecting EBV genomic LMP-1 by nasopharyngeal swab diagnosed NPC with 87.3% sensitivity and 98.4% specificity. EBV genomic DNA usually is not detected by PCR-based methods in the nasopharyngeal space. Its incidence is estimated to be as low as 0.2% among the general population. The nasopharyngeal swab coupled with PCR-based EBV LMP-1 detection could serve as part of a screening program for high-risk populations.
Hao
Sheng-Po
SP
Department of Otolaryngology, Chang Gung Memorial Hospital, Chang Gung University, Taipei, Taiwan, Republic of China. shengpo@adm.cgmh.org.tw
Tsang
Ngan-Ming
NM
Chang
Kai-Ping
KP
D000956:Antigens, Viral / Q000235:genetics*; D014408:Biomarkers, Tumor / Q000032:analysis; D017931:DNA Primers / Q000737:chemistry; D004279:DNA, Viral / Q000032:analysis*; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D008403:Mass Screening; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis* / Q000821:virology*; D009305:Nasopharynx / Q000166:cytology; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013624:Taiwan; D014763:Viral Matrix Proteins / Q000235:genetics*
D000956:Antigens, Viral; D014408:Biomarkers, Tumor; D017931:DNA Primers; D004279:DNA, Viral; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D014763:Viral Matrix Proteins