Sinonasal lymphomas in Indonesia: immunophenotype and Epstein-Barr virus association.

Sinonasal lymphoma is a rare disease with NK/T-cell (NKTC) or B-cell immunophenotype. Previous study revealed the geographic difference in frequency of NKTC lymphoma (NKTCL) and almost constant association with Epstein-Barr virus (EBV) infection. Through review of 41 cases with sinonasal lymphoproliferative diseases registered in the Department of Anatomical Pathology, University of Indonesia during the period 1994 to 2002, thirty-five were accepted as sinonasal lymphoma. Immunohistochemistry revealed that 20 cases (57%) were NK/T-cell type and 15 (43%) B-cell type with large cell morphology, i.e.,diffuse large B-cell lymphoma. NKTCL showed a marked male preponderance (M/F= 4:1) and younger onset of disease (median age, 37 years), and B-cell lymphoma showed a relative female preponderance (1:1.5) and older disease onset (median age, 49 years). In situ hybridization using EBER-1 probe revealed that 90% of NKTCL were EBV-positive, but none of B-cell lymphoma were EBV-positive. This is the first report on sinonasal lymphoma in Indonesia showing relative predominance of B-cell lymphoma compared to other Asian countries and Peru (14-24%). Lack of EBV-association in Indonesian sinonasal B-cell lymphoma showed a marked contrast to that in other Asian countries (EBV positive rate, 25-41 %). Predominance of sinonasal B-cell lymphoma without EBV genome might suggest presence of specific etiologic factors in Indonesia.

Evaluation of EBV-LMP1 as prognostic indicator of nasopharyngeal carcinoma in Indonesian patients.

Forty eight cases of nasopharyngeal carcinoma patients who had been treated with radiotherapy were analysed for the expression of EBER in the nucleus of the tumor cells by in situ hybridization technique. EBER was expressed in 69% of the cases. Histologic specimens positive for EBER were then examined for the expression of EBV-LMP1 by immunohistochemistry, which showed 68% positivity. Clinical staging of 48 cases and radiation response of 32 cases were collected. Data of up to 2 years of survival of 16 cases were obtained through postal and phone communication. Statistical analysis showed that the Working Formulation histologic classification of NPC correlated significantly with radiation response. The expression of EBV-LMP1 was correlated significantly with the survival of the patients. Thus EBV-LMP1 which has been shown to possess influence on lymphoid and epithelial cells, clinicopathologically proved to have a function as prognostic indicator.