The 30-bp deletion from LMP-1 gene in the clinicopathological manifestation of NPC tumors

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Problem: The 30-bp deletion in the carboxy-terminal region of the Epstein-Barr virus-derived latent membrane protein-1 gene has been proved to be associated with carcinogenesis of nasopharyngeal carcinoma (NPC), a common head and neck cancer in Taiwan. We conducted a retrospectively prospective cohort study to investigate whether this sequence deletion did play any role in the clinicopathological manifestation of NPC Methods: Between 1994 and 2003, 242 NPC patients who received the complete course of radiotherapy followed by at least 2-year follow-up were enrolled. Patients were divided into 2 groups according to the presence or absence of the 30-bp deletion. Patients’ initial clinicopathological manifestations, radiosensitivity, distant metastasis status, and overall survival were analyzed. Results: A total of 197 (81.4%) patients were found to have the 30-bp deletion and 42 (17.4%) did not. Surprisingly, 3 (1.2%) patients had the dual infection. Age, sex, presenting stage, locoregional radiosensitivity, and pathological classification all lack statistical difference between 2 groups. In survival analysis, the actuarial 5-year overall survival, distant metastasis-free rate, and disease-free survival of nondeletion group tend to be better than those of the 30-bp deletion group (71.6% vs 59.0%, 87.4% vs 70.2%, and 43.2% vs 39.5%). In multivariate analysis, we discovered that older NPC patients with the 30-bp deletion and the patients presenting with advaced tumor stages have worse prognosis in the overall survival. Conclusion: 81.4% of Taiwanese NPC patients had the 30-bp deletion. Our findings indicate that this sequence deletion has no effect on clinicopathological manifestations but tends to be a worse prognostic factor in the overall survival and distant metastasis. Our study also demonstrated that dual infection is a rare but possible phenomenon in NPC tumors. Significance: Our studies indicate that this 30-bp deletion has no effect on the NPC’s various clinicopathological manifestations, but the negative impact of the 30-bp deletion to overall survival will be enlarged as patient’s age increases. Support: This study was supported by grants from the Taiwan National Science Council (NSC88-2314-B-182A-010, NSC92-2314-B-182A-207) and Chang Gung University (CMRPG32077, CMRPG32090).