Tunisia is one of the world’s intermediate risk areas for nasopharyngeal carcinoma (NPC). Loss of heterozygosity (LOH) on the short arm of chromosome 3 (3p) is the most frequent genetic change reported in NPC from endemic areas. In the present study, we investigate the incidence of LOH and microsatellite instability (MSI) on chromosome 3p in 49 microdissected primary NPC specimens and corresponding non-cancerous tissues from Tunisian patients using six microsatellite polymorphic markers. LOH at one or more markers was observed in 40 out of 48 informative cases (83.3%). The markers D3S1038 at 3p25.2–26.1 and D3S1076 at 3p21.1–21.2 have showed the highest frequency of LOH (51.3%), followed by D3S1067 at 3p14.3–21.1 (48.7%), D3S1568 at 3p21.3 (47.4%), D3S659 at 3p13 (15.3%), and D3S1228 at 3p14.1–14.2 (11%). Interestingly, MSI at one or more microsatellite markers was observed in 15 cases (31.2%). The highest frequency of MSI was presented by D3S1568 (18.4%), D3S1067 (17.9%), and D3S1038 (12.8%). With regard to clinicopathological features, LOH was found to be less common in young patients (under 25 years) than in adults (p=0.04), whereas MSI was found to be more frequent in patients under 45 years than in older patients (p=0.006). No significant correlation was found between LOH or MSI and the other clinicopathological features investigated including, gender, tumor size, lymph node metastasis, UICC clinical stage, and histological subtype. This study revealed different patterns of allelic imbalance on chromosome 3P in NPC between age groups in Tunisia, and suggests an alteration in the DNA mismatch repair machinery that may be, in part, responsible of the early age onset form of this disease in North African populations. More attention should be given to the mismatch repair system in the juvenile form of this disease in future studies.

CD10 is a cell surface zinc metalloprotease expressed through a variety of normal cell types, including lymphoid precursor cells, germinal center B lymphocytes, and some epithelial cells. Many studies showed that CD10 expression is associated with the tumor progression of a large variety of cancers, such as breast and colorectal carcinomas. The aim of this study was to investigate the expression of CD10 in nasopharyngeal carcinoma (NPC). The expression of CD10 was immunohistochemically examined in 47 paraffin embedded NPC biopsies from Tunisian patients compared with 16 reactional nasopharyngeal mucosas. A significant expression of CD10 was observed in stromal fusiform cells in 46.8% of NPC cases but was not in malignant and normal epithelial cells. There was no significant expression of CD10 in control group. The stromal expression of CD10 was more frequently detected in advanced clinical stage than early stage (56 vs 23%; p=0.04) and in patients older than 25 years than in patients under 25 years (56.2 vs 26.5%; p=0.05). Our study is the first in investigating CD10 expression in nasopharyngeal carcinoma and showed that CD10 expression by stromal cells in this malignancy play an important role in tumor progression, particularly in older patients.

Purpose. - The cause of Sjogren's syndrome is unclear. Several studies suggested the role of Epstein-Barr virus (EBV) in the pathogenesis of this syndrome, but this always remains a subject of numerous controversies. The purpose of this study was to evaluate the prevalence of EBV in Sjogren's syndrome in Tunisia.Methods. - A series of 31 paraffin-embedded biopsies of salivary glands from patients with Sjogren's syndrome were studied in comparison with 19 control glands. EBV was investigated by PCR, EBERs in situ hybridization and by immunohistochemistry for the detection of LMP1, EBNA2 and ZEBRA.Results. - EBV DNA was detected by PCR in 3 of 22 PCR beta-globin positive Sjogren's syndrome cases (13.6%) and in 2 of 17 PCR beta-globin positive control glands (11.7%); in situ hybridization positivity was noted in rare lymphocytes in the 3 EBV positive cases of Sjogren's syndrome, but not in control glands; immunohistochemical study was negative in all cases.Conclusion. - EBV infection does not appear to play a significant role in the pathogenesis of Sjogren's syndrome in Tunisia. (C) 2006 Publie par Elsevier SAS.