Correlation of immunophenotype of sinonasal non-Hodgkin's lymphoma to Epstein-Barr virus infection.

Background & Objective: There are differences in the prevalence rate and composition of immunophenotypes of sinonasal non-Hodgkin's lymphoma (NHL) depending on the geography. This study was to investigate the immunophenotypes of sinonasal NHLs and their relationship to Epstein-Barr virus (EBV) infection in Guangzhou, China.

Methods: Fifty-seven NHL samples of the sinonasal region were collected from the Department of Pathology, Cancer Center of Sun Yat-sen University from Apr. 1, 2000 to Oct. 31, 2006. HE staining and immunohistochemical staining were performed. Both Epstein-Barr virus-encoded small RNA (EBER) hybridization and PCR were applied to identify EBV infection.

Results: Seventy-one sinonasal NHLs were found in all 1 412 NHLs (71/1 412, 5.03%). Only 57 out of the 71 NHL biopsy tissues were suitable for this study. The median age of the patients was 50 years (ranged from 3 to 75 years). There were 38 males and 19 females. Forty-four sinonasal NHLs (44/57, 77.19%) were NK/T-cell lymphoma, nasal type, all of which were infected with EBV. Among them, 37 patients (84.09%) appeared to be NK-cell neoplasm (EBV+/CD56+), and 7 cases (15.91%) showed an EBV+/CD56-cytotoxic T-cell phenotype. Eleven cases (11/57, 19.30%) were B-cell lymphoma. There were 6 cases of diffuse large B-cell immunophenotype, 2 cases of Burkitt (Burkitt-like) lymphoma (EBV+), 1 case of extramedullary plasmacytoma (EBV+), 1 case of MALT-lymphoma (EBV-), and 1 case of small lymphocytic lymphoma (EBV-). Only 2 cases (2/57, 3.51%; EBV-) were peripheral T-cell lymphoma, unspecified. The del-LMP1 EBV strain harbored in 25 out of 37 available DNA samples of NK/T-cell lymphoma (25/37, 67.57%); and the wt-LMP1 EBV strain was found in 12 samples (12/37, 32.43%).

Conclusion: The most common sinonasal NHL is the NK/T-cell lymphoma, nasal type, which can be further subclassified into NK-cell neoplasm (EBV+/CD56+) and EBV+/CD56-cytotoxic T-cell phenotype. The major EBV strain in NK/T-cell lymphomas is del-LMP1 strain.