Epigenetic markers for early detection of nasopharyngeal carcinoma in a high risk population

Abstract

BackgroundUndifferentiated nasopharyngeal carcinoma (NPC) is strongly related to Epstein-Barr virus (EBV) infection, allowing aberrant antibodies against EBV and viral DNA load as screening tools in high risk populations. Methylation analysis in the promoter of tumor suppressor genes (TSGs) may serve as a complementary marker for identifying early cases. This study determined methylation status of multiple TSGs and evaluated whether it may improve early detection.MethodsNasopharyngeal brushings were taken from 53 NPC patients, 22 high risk subjects and 25 healthy EBV carriers. Corresponding NPC paraffin tissue was included. DNA was bisulfite-modified preceding analysis by methylation-specific PCR (MSP). Ten TSGs were studied.ResultsNPC paraffin and brushing DNA revealed an 81.8% concordance so that MSP analysis was done using either one of both specimens. NPC samples showed methylation for individual TSGs (DAPK1 79.2%, CDH13 77.4%, DLC1 76.9%, RASSF1A 75.5%, CADM1 69.8%, p16 66.0%, WIF1 61.2%, CHFR 58.5%, RIZ1 56.6% and RASSF2A 29.2%). High risk individuals, having elevated EBV IgA and viral load, showed high frequency of methylation of CDH13, DAPK1, DLC1 and CADM1, but low frequency of methylation of p16 and WIF1 and undetectable methylation of RASSF1A, CHFR, RIZ1 and RASSF2A. Healthy subjects showed similar patterns as high risk individuals. A combination of RASSF1A and p16 gave good discrimination between NPC and non-NPC, but best results were combined analysis of five methylation markers (RASSF1A, p16, WIF1, CHFR and RIZ1) with detection rate of 98%.ConclusionMultiple marker MSP is proposed as a complementary test for NPC risk assessment in combination with EBV-based markers.

Epigenetics of Nasopharyngeal Carcinoma

“…So methylation assessment of single genes lacks sufficient specificity for NPC diagnosis. It is believed that panels of multiple methylation biomarkers may achieve higher accuracy required for discriminate NPC from other cancers Hutajulu et al 2011). This notion was supported by a study of Esteller et al, which showed that a panel of three to four markers could define an abnormality in 70-90% of each cancer type through detecting their aberrant methylation (Esteller et al 2001).…”

“…Combination of methylation markers not only improved the discrimination between NPC and non-NPC diseases, but also the sensitivity of cancer detection. The detection rate can reach 98% when combined analysis of five methylation markers (RASSF1A, p16, WIF1, CHFR and RIZ1) in a recent study (Hutajulu et al 2011). …”

Up-Regulation of Lamin A/C Expression in Epstein-Barr Virus Immortalized B Cells and Burkitt Lymphoma Cell Lines of Activated B Cell Phenotype

“…Strikingly, overlapping hypomethylated blocks of 1.7 GB were also observed in the epigenomes of unrelated EBV-negative carcinomas, including colon, lung, breast and thyroid carcinomas and Wilms' tumors [54]. This implies that tumor-specific methylation changes may be used as biomarkers in methylation-specific diagnostic PCR assays from the blood for the early detection of occult tumors [63][64][65]. Furthermore, hypermethylation at specific tumor suppressor loci may serve as a predictor for the success of chemotherapy [66,67].…”

Mixed Exocrine-Neuroendocrine Carcinoma of the Nasal Cavity: Clinico-Pathologic and Molecular Study of a Case and Review of the Literature

“…Promoter hypermethylation of DAPK1 was also found to be restricted to the neuroendocrine component. Interestingly, the aberrant methylation of DAPK1 is considered an important epigenetic event in nasopharyngeal carcinomas [34] and has been evaluated as an early molecular marker of subclinical presence of this neoplasm [35,36].…”