No abstract

There are two types of Epstein Barr virus (EBV): EBV-1 and EBV-2, distinguished by genomic polymorphism in the genes encoding the nuclear antigens (EBNA-2, -3A, -3B, -3C). Latent membrane protein 1 (LMP-1) is an EBV protein with known oncogenic properties. Different variants had been described; among them, a 30 base pair (bp) deletion (del-LMP-1) had been reported in benign and malignant pathologies, but there is little information about its frequency in healthy populations. The aim of this study was to determine the distribution of the EBV genotypes and the 30 bp deletion frequency, in EBV healthy carriers from Argentina. Analysis of EBNA-3C and LMP-1 genes were done by polymerase chain reaction (PCR) followed by Southern blot hybridization on DNA of peripheral blood mononuclear cells (PBMCs) from blood bank donors. EBV-1 was present in 75.9% of samples, EBV-2 in 14.6%, and co-infections with both types in 6.5%. The deleted LMP-1 variant was found in 7.4% of analyzed samples, corresponding 3.2% to deleted variant alone and 4.2% to co-infections with non-deleted form. The non-deleted variant was found in 64.6% whereas in the remaining 28%, no PCR product was detected. These results showed that EBV-1 was the more prevalent type in healthy carriers of Argentina, similar to reports from others countries. A predominance of the non-deleted LMP-1 variant was observed. The presence of co-infections with both types and variants demonstrated that healthy individuals may also harbor multiple EBV infections.

Among sexually transmitted diseases, infection by human papillomavirus (HPV) has become one of the most important. On the other hand, though epidemiological data show that some HPV types are closely associated with cervical cancer, few reports have been found with reference to penile carcinoma because of its rare occurrence. The aim of this study was to investigate the relationship between HPV infection and penile cancer in Argentina. A retrospective study was carried out on 38 white men with penile squamous-cell carcinoma. Sixty-five archival fixed biopsies taken from 34 primary penile tumors, 25 nodal metastases, 1 skin "satellite" metastasis and 5 histologically normal lymph nodes were used as specimens. HPV detection and typing were carried out by the polymerase chain reaction (PCR) using generic primers, combined with single-stranded conformational polymorphism (SSCP) analysis. HPV DNA was found in 71% patients, corresponding 81% of them to "high risk" types, with predominance of HPV 18. Both primary tumors and metastases showed concordance of HPV occurrence and type in both lesions. In 3 patients, HPV 16 was detected not only in primary tumors and metastases, but also in histologically normal lymph nodes. Our data indicate that most penile carcinomas in Argentine patients are etiologically related to HPV, especially to "high risk" genital types. The agreement in HPV detection between primary tumors and metastases suggests a potential viral role in tumor progression. HPV detection in otherwise histologically normal lymph nodes might be useful as early marker of a metastatic process.

Cervical carcinoma is the leading cause of cancer death in Quechua indians from Jujuy (northwestern Argentina). To determine the prevalence of HPV-16 variants, 106 HPV-16 positive cervical samples were studied, including 33 low-grade squamous intraepithelial lesions (LSIL), 28 high-grade squamous intraepithelial lesions (HSIL), 9 invasive cervical cancer (ICC), and 36 samples from women with normal colposcopy and cytology. HPV genome variability was examined in the L1 and E6 genes by PCR-hybridization. In a subset of 20 samples, a LCR fragment was also analyzed by PCR-sequencing. Most variants belonged to the European branch with subtle differences that depended on the viral gene fragment studied. Only about 10% of the specimens had non-European variants, including eight Asian-American, two Asian, and one North-American-1. E6 gene analysis revealed that 43% of the samples were identical to HPV-16 prototype, while 57% corresponded to variants. Interestingly, the majority (87%) of normal smears had HPV-16 prototype, whereas variants were detected mainly in SIL and ICC. LCR sequencing yielded 80% of variants, including 69% of European, 19% Asian-American, and 12% Asian. We identified a new variant, the Argentine Quechua-51 (AQ-51), similar to B-14 plus two additional changes: G7842-->A and A7837-->C; phylogenetic inference allocated it in the Asian-American branch. The high proportion of European variants may reflect Spanish colonial influence on these native Inca descendants. The predominance of HPV-16 variants in pathologic samples when compared to normal controls could have implications for the natural history of cervical lesions.