Pathoepidemiology of Epstein-Barr virus infection and peculiar necrosis in nasal NK/T-cell lymphomas in northeast China.

Nasal NK/T-cell lymphoma (NKTCL) is an Epstein-Barr virus (EBV)-associated lymphoma when the close relationship between nasal NKTCL in Japan and EBV infection was elucidated by Harabuchi et al (Lancet，1990) and the EBV infection in NKTCL is of Latency Ⅱ (Takahara et al. Human Pathol. 2004). Recently predominant occurrence of nasal NKTCL was observed in China， even in the northeast region (Zhonghua Bing Li Xue Za Zhi. 2007). This study analyzed pathoepidemiologically EBV infection in 134 cases of nasopharyngeal lymphomas diagnosed clinically in the northeast China and investigated immunohistochemically peculiar necrosis in 40 cases of nasopharyngeal lymphomas. Most of 85 cases of T/NK-cell neoplasms (T-ML) were so-called nasal NKTCL comprising 5 cases of early NKTCL(Polymorphous reticulosis:PR)，65 cases of NKTCL and 9 cases of cytotoxic T-cell lymphomas.24 of 35 cases of B-cell lymphomas (B-ML) were of diffuse large B-cell lymphoma (DLBCL) and 9 cases of small cancers were seen. Frequent occurrence of NKTCL in nasal cavity and in male and frequent occurrcnce of B-ML in pharynx，and their rare occurrence of B-ML under 40 years of Age were significant. 71 cases of NKTCL were EBV-associated when 5 cases were not and lymphoma cells with and without EBV infection were noted in the others. In the residual epithelial lesions in 26 cases of T-ML and 7 cases of B-MLs there were EBV-not-associated and survivin-positive minute squarmous carcinoma in 11 cases of EBV-associated NKTCL. EBV-associated NKTCL revealing peculiar necrosis did not show cleaved casapse-3-positive apoptotic lymphoma cells and expressed survivin，different from the previous reports based on so-called cell line research (Jeon et al.，Ko et al.Lab Invest.2005，2007)，expressed Beclin-1 (Atg6) and showed macrogranular staining of LC3 (Atg8)，suggesting elevated autophagy. In the peculiar necrosis with naked nucleus-like cell debris，dense nuclear/peri-nuclear staining of LC3 was a hallmark of autophagic cell death. Consequently，EBV-not-associated NKTCL cells and minute squarmous carcinoma in the NKTCL suggested microenvironmental factors other than EBV in the occurrence of NKTCL as suggested epidemiologically (Xu et al.Int J Cancer.2007)