Multilaboratory Assessment of Epstein-Barr Virus Serologic Assays: the Case for Standardization.

IgA antibodies targeting Epstein-Barr virus (EBV) have been proposed for screening for nasopharyngeal carcinoma (NPC). However, methods differ, and the antigens used in these assays differ considerably between laboratories. To enable formal comparisons across a range of established EBV serology assays, we created a panel of 66 pooled serum samples and 66 pooled plasma samples generated from individuals with a broad range of IgA antibody levels. Aliquots from these panels were distributed to six laboratories and were tested by 26 assays measuring antibodies against VCA, EBNA1, EA-EBNA1, Zta, or EAd antigens. We estimated the correlation between assay pairs using Spearman coefficients (continuous measures) and percentages of agreement (positive versus negative, using predefined positivity cutoffs by each assay developer/manufacturer). While strong correlations were observed between some assays, considerable differences were also noted, even for assays that targeted the same protein. For VCA-IgA assays in serum, two distinct clusters were identified, with a median Spearman coefficient of 0.41 (range, 0.20 to 0.66) across these two clusters. EBNA1-IgA assays in serum grouped into a single cluster with a median Spearman coefficient of 0.79 (range, 0.71 to 0.89). Percentages of agreement differed broadly for both VCA-IgA (12% to 98%) and EBNA1-IgA (29% to 95%) assays in serum. Moderate-to-strong correlations were observed across assays in serum that targeted other proteins (correlations ranged from 0.44 to 0.76). Similar results were noted for plasma. We conclude that standardization of EBV serology assays is needed to allow for comparability of results obtained in different translational research studies across laboratories and populations.

Assessment of pain score and specimen adequacy for ultrasound-guided fine-needle aspiration biopsy of thyroid nodules.

OBJECTIVE: The aim of this study was to evaluate pain scores and specimen adequacy for ultrasound-guided fine-needle aspiration biopsy (US-FNAB) of thyroid nodules without and with local anesthesia (LA). MATERIALS AND METHODS: The US-FNAB procedure was performed on 183 patients with and without LA. One puncture was made for solid nodules, and if patients could tolerate it, a two-puncture technique was used for nodules with a cystic change. Four-point verbal rating scores were assessed by a nursing assistant after completion of US-FNAB. To be an adequate specimen, at least six groups of follicular cells are required, and each group should contain at least 10 cells. RESULTS: Immediately after US-FNAB, 92% of patients with LA and 80% without LA reported no or mild pain (p=0.01). Most patients tolerated the procedure well, with no pain (82.5%) reported 5 minutes after the procedure. In univariate logistic regression, irregular boundary (odds ratio [OR]: 2.52, 95% confidence interval [CI]: 1.04-6.06, p=0.04), calcification (OR: 2.86, 95% CI: 1.06-7.76, p=0.04), and LA (OR: 0.35, 95% CI: 0.15-0.86, p=0.02) were significantly associated with immediate moderate or severe pain. Specimen adequacy was significantly associated with age (OR: 0.95, 95% CI: 0.92-0.97, p<0.01), heterogeneous echo-texture (OR: 1.76, 95% CI: 1.23-5.17, p=0.01), predominate solid architecture (OR: 2.78, 95% CI: 1.42-5.41, p<0.01), and the use of LA (OR: 3.34, 95% CI: 1.70-6.56, p<0.01). In multivariate logistic regression, patients receiving LA had lower risk of moderate or severe pain (OR: 0.25, 95% CI: 0.09-0.67, p=0.01) and higher chances of specimen adequacy (OR: 4.84, 95% CI: 2.17-10.7, p<0.01) compared to patients who did not receive LA. CONCLUSION: US-FNAB is a safe procedure, and most patients report no pain 5 minutes after the procedure. The use of LA was associated with lower immediate pain scales and higher specimen adequacy.

Revisit of field cancerization in squamous cell carcinoma of upper aerodigestive tract: better risk assessment with epigenetic markers.

We quantified field cancerization of squamous cell carcinoma in the upper aerodigestive tract with epigenetic markers and evaluated their performance for risk assessment. Methylation levels were analyzed by quantitative methylation-specific PCR of biopsied specimens from a training set of 255 patients and a validation set of 224 patients. We also measured traditional risk factors based on demographics, lifestyle, serology, genetic polymorphisms, and endoscopy. The methylation levels of four markers increased stepwise, with the lowest levels in normal esophageal mucosae from healthy subjects without carcinogen exposure, then normal mucosae from healthy subjects with carcinogen exposure, then normal mucosae from cancer patients, and the highest levels were in cancerous mucosae (P < 0.05). Cumulative exposure to alcohol increased methylation of homeobox A9 in normal mucosae (P < 0.01). Drinkers had higher methylation of ubiquitin carboxyl-terminal esterase L1 and metallothionein 1M (P < 0.05), and users of betel quid had higher methylation of homeobox A9 (P = 0.01). Smokers had increased methylation of all four markers (P < 0.05). Traditional risk factors allowed us to discriminate between patients with and without cancers with 74% sensitivity (95% CI: 67%-81%), 74% specificity (66%-82%), and 80% area under the curve (67%-91%); epigenetic markers in normal esophageal mucosa had values of 74% (69%-79%), 75% (67%-83%), and 83% (79%-87%); and both together had values of 82% (76%-88%), 81% (74%-88%), and 91% (88%-94%). Epigenetic markers done well in the validation set with 80% area under the curve (73%-85%). We concluded that epigenetics could improve the accuracies of risk assessment.