Epstein barr virus in head and neck extranodal non-hodgkin’s lymphoma in Egypt

الملخص EN

Background : primary extranodal lymphoma of the head and neck (PELHN) represents 16.18 % of all malignant lymphoma cases diagnosed at the NCI, Cairo University between 1985-1990.

Epstein Barr virus (EBV) infection is highly associated with lymphoma in immune-compromised patients however ; the situation in immune-competent patients is still unclear.

Material and methods : we investigated 50 PELHN, 5 reactive lymph nodes, 15 normal nasopharyngeal tissue (NPTs) and 25 throat washes (TW) of healthy people from Egypt for EBV association, expression of p53, Ki-67, bcl-2, Box and the clinical outcome.

Results : phenotypic analysis showed that 31 cases were B cell and 19 were T cell lymphomas.

Eleven cases were present in the nose and Para nasal sinuses, 11 in the nasopharynx, 13 in the tonsils, 7 in the oropharynx and 8 in the oral cavity.

EBV positivity was reported in 90 % and 70 % of the cases using EBER in situ hybridization and PCR respectively (concordance = 70 %).

All cases of nasal type lymphoma were EBV positive.

Strain typing revealed the presence of type 1 in all positive cases.

30 base pair deletion of the LMP-1 (del-LMP1) gene was detected in 24 / 35 EBV-positive cases by PCR (68.6 %) whereas 11 cases had wild type variant either alone or mixed with del-LMP1.

There was a statistically significant difference in the frequency of del-LMP1 between lympho-ma and normal tissues.

Overexpression of Ki-67, p53 and bcl-2 was detected in 78.1 %, 62.5 % and 20 % of cases whereas absence of Box was reported in 18 % of cases.

Univar ate analysis showed that p53 overexpression, a high Ki-67 index ; advanced disease stage and T phenotype are poor prognostic factors whereas only p53 overexpression and advanced disease stage are poor prognostic factors in multivariate analysis.

Conclusion : EBV infection is frequent in PELHN in Egypt.

Possible pathogen etic mechanisms involve deregulation of p53 and enhanced proliferation (as detected by high Ki-67 index).

The presence of del-LMP1 variants, p53 overexpression and advanced disease stage are poor prognostic factors associated with reduced survival and poor response to therapy.