Distribution of Epstein–Barr virus genotypes in throat washings, sera, peripheral blood lymphocytes and in EBV positive tumor biopsies from Slovenian patients with nasopharyngeal carcinoma

Abstract

Nasopharyngeal carcinoma (NPC) is a malignancy closely associated with Epstein-Barr virus (EBV). It is prevalent among the Chinese of Southern China, whereas outside China, the position seems to be different. The aim of this study was to determine the distribution of EBV genotypes in the patients with NPC in Slovenia, which is a nonendemic area. Detection of EBV was undertaken by testing the throat washes, sera, peripheral blood lymphocytes (PBLs), and biopsies of primary tumors of 48 patients with NPC in Slovenia. The sera of 20 patients with serologically confirmed primary EBV infection served as a control clinical material. The analysis of genotypes was carried out on three regions of EBV genome; BamHI WYH, BamHI I, and BamHI F, using the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The results show that, in Slovenia, the predominant combination of EBV genotypes based on the differences in the three genomic regions is ADF. This combination was found in 56 out of 103 different EBV positive clinical samples (throat washes, sera, PBLs, and tumor biopsies) of patients with NPC and in 15 out of 17 sera of patients with primary EBV infection. Very low number of genotypes C and f were detected, in spite of the fact that these two genotypes were considered to be associated with the development and/or maintenance of NPC in Southern China. Genotype f was found in only two tumor biopsies; in all other clinical samples (throat washes, sera and PBLs), genotype F was detected. Genotype C was proven in 31/103 clinical samples, with the highest percentage in tumor biopsies (37.5%). As in the NPC patients from other countries (Alaska is an exception), genotype A was predominant and was detected in 86/103 clinical samples. Genotype B was found in 15 clinical samples of patients with NPC and in 3 the two genotypes A and B were found. In comparison to China, these results show different EBV genotypes distribution. It seems that the genetic disposition of human population is an important factor that may contribute to different susceptibility for specific EBV genotypes.

Genotypic Analysis of Epstein-Barr Virus Isolates Associated with Nasopharyngeal Carcinoma in Northern China

“…0.05). Similar to our results, the f variant was rare in other areas, such as Japan, Korea, Europe, North America, South America and Africa ignoring the source (healthy donors and malignant patients) [10,11,24,27,30,31] . In addition, the F variant was dominant in patients with other EBV-associated diseases (18/19 T cell lymphoma, 3/3 infectious mononucleosis and 37/45 EBV-associated gastric carcinoma) in Southern China [22] , whereas the f variant was only prevalent in NPC of Southern China.…”

“…Tamura et al [11] and Sidagis et al [14] also detected the presence of type C in 7/10 (70%) NPC tissues and 50/54 (92.6%) TWs of healthy donors in Japan. Contrary to most districts of Asia, type D was found to be common in NPC tissues from Europe and North Africa where there is an intermediate incidence of NPC [8,10] . In Slovenia and Tunisia, type D strain was found in 30/48 and 46/47 NPC biopsies, respectively [10,27] .…”

“…Contrary to most districts of Asia, type D was found to be common in NPC tissues from Europe and North Africa where there is an intermediate incidence of NPC [8,10] . In Slovenia and Tunisia, type D strain was found in 30/48 and 46/47 NPC biopsies, respectively [10,27] . In addition, the presence of the type D virus was also found in 10/12 (83.3%) Caucasian NPC patients and in 29/36 (81%) healthy donors from the United States [13,28] .…”

“…It has been reported that the incidence of EBV infection varies geographically [8] . Type A is predominant in Southern China, Japan, Tunisian, Slovenia, and North America, whereas type B has been found mainly in Alaska [3,[9][10][11][12] . A further attempt to identify polymorphisms of virus isolates in the Bam HI I and Bam HI F region of the EBV genome resulted in the so-called type C/D and type F/f, which represent single nucleotide polymorphisms at Bam HI sites on the viral genome.…”

Genotypic analysis and latent membrane protein 1 expression of Epstein-Barr virus in extranodal NK/T-cell lymphoma from Northern Chinese patients

“…Sidagis et al detected the presence of type C in 61 of 63 and F in 63 of 64 of EBV-related gastric cancers, C in 8 of 11(72.7 %) and F in 11 of 11 EBV-related T/NK-cell lymphomas, and C in 7 of 10 (70 %) NPCs in Japan [6]. In contrast, type D was found to be common in patients with NPC from Europe and North Africa [20,21]. In addition, the F variant dominated in patients with other EBV-associated diseases such as T cell lymphoma, infectious mononucleosis, EBV-associated gastric carcinoma in southern China, whereas the f variant was only prevalent in NPC in southern China [13,22].…”