Roles of DNA cytometry and detection of EBERs in predicting a diagnosis of nasopharyngeal carcinoma.

ABSTRACT

OBJECTIVE: To analyze the suitability of DNA cytometry and detection of Epstein-Barr virus (EBV)-encoded RNAs (EBERs) on nasopharyngeal brushings for predicting a diagnosis of nasopharyngeal carcinoma (NPC). STUDY DESIGN: Cytologic preparations in 66 cases suspicious for NPC were evaluated for NPC diagnosis in comparison with the histologic diagnosis. Based on cytologic examination, 38 cases containing cytologically proven cancer and 8 cases interpreted as cytologically negative for cancer with adequate cellularity in the smear specimens were analyzed for DNA ploidy with an image analyzer and for EBER expression by in situ hybridization (ISH). RESULTS: Based on the cytologic diagnosis, DNA aneuploidy analysis, DNA nondiploidy analysis and EBER detection demonstrated a sensitivity of 50%, 84% and 92%, respectively, with the same specificity, 100%, for predicting a diagnosis of cancer. Their negative predictive values were 30%, 57% and 73%, respectively. There was a significant difference between DNA aneuploidy analysis and EBER analysis in sensitivity (P < .001) and in negative predictive value (P < .05) but not between DNA nondiploidy analysis and EBER analysis even though EBER analysis showed a slightly higher value in both parameters (P > .1 and P > .5, respectively). CONCLUSION: ISH for EBERs in cytologic smears showed a role superior to that of DNA aneuploidy analysis in the diagnosis of NPC. Considering its advantages of simple experimental conditions and lower cost as compared with DNA measurement, EBER detection can play a practical and important diagnostic role in patients suspected of having primary NPC.