**4. Conclusion**

EBV is associated with the development of both B-cell and epithelial cell malignancies. The capacity of EBV to transform B lymphocytes has been well documented. EBV latent proteins are known to contribute to cellular transformation. Several lines of evidence demonstrated that reactivation of the latent viral genome in EBV associated cancers can cause cancer cell death. However, the underlying molecular mechanisms are unclear. Although ZEBRA plays an important role in immunomodulation, its capacity to reprogram the hosT-cell cycle control machinery is also notified in some tumour cell lines. Therefore, gene delivery techniques might be a novel therapeutic strategy for treating EBV positive malignancies especially NPC, via the induction of lytic viral transcription in certain tumour cells.

HPV-associated nasopharyngeal carcinoma represents a distinct clinical and biological entity with many unresolved issues that will be studied in future translational, clinical

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#### **5. References**


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**4** 

*Changsha, Hunan,* 

*Changsha, Hunan,* 

*P.R. China* 

**Chemical Carcinogenesis and** 

Faqing Tang1, Xiaowei Tang2, Daofa Tian3 and Ya Cao4

*2Metallurgical Science and Engineering, Central South University, Changsha, Hunan,* 

*4Cancer Research Institute of Xiangya School of Medicine, Central South University,* 

The non-viral exposure that is most consistently and strongly associated with risk of nasopharyngeal carcinoma (NPC) is the consumption of salt-preserved fish, a traditional staple food in several NPC-endemic areas [1]. In studies of the Chinese population, the relative risk of NPC associated with weekly consumption of salt-preserved fish generally ranges from 1.4 to 3.2, whereas the risk for daily consumption ranges from 1.8 to 7.5 [2-7]. This indicates that consumption frequency of salt-preserved fish is associated with the risk of NPC. However, elevated NPC risk is also associated with other preserved food items,

In southern China, intake of salted and other preserved foods is particularly high among boat-dwelling fishermen and their families, this is also the population subgroup at highest risk of developing NPC [16]. Salt-preserved foods are a dietary staple in all NPC-endemic populations [14, 17]. Furthermore, salted fish is a traditional weaning food and is fed early and frequently to infants, especially in the Cantonese population [4, 14] and in families of lower socioeconomic status [3, 18]. Childhood exposure, especially at weaning, appears to be more strongly related to NPC risk than exposure during adulthood [3, 4, 14, 15, 17, 19- 21]. This dietary association may partly explain the international distribution of NPC

The carcinogenic potential of salt-preserved fish is supported by experiments in rats, which develop malignant nasal and nasopharyngeal carcinoma [22-24]. The process of salt preservation is inefficient, allowing fish and other foods to become partially putrefied [25, 26]. As a result, these foods accumulate significant levels of nitrosamines, which are known carcinogens [25, 27-29]. Consumption of salted fish is a significant source of nitrosamines. Total volatile N-nitrosamines, consisting of N-dimethylnitrosamine, N-diethylnitrosamine, N-nitrosopyrrolidine, and N-nitrosopiperidine, are present in salted fish at concentrations of

**1. Introduction** 

incidence.

**1.1 Epidemiology of nasopharyngeal carcinoma** 

including meats, eggs, fruits, and vegetables [4-15].

*3The First Affiliated Hospital, The Hunan University of Traditional- Chinese,* 

**Nasopharyngeal Carcinoma** 

*1Zhuhai Hospital, Jinan University, Guang Dong,* 

