Brazilian Journal of Microbiology

Epstein-barr virus (EBV) in cervical carcinoma detected by in situ hybridization targeting ebers and the viral genome

Epstein-Barr virus (EBV) infection has been suggested as a potential cofactor for the development and progression of cervical cancer, collaborating with high-risk Human Papillomavirus (HR-HPV). In situ hybridization (ISH) has been considered the gold standard in the investigation of EBV in neoplasms. This study aimed to detect EBV in cervical carcinoma samples using ISH targeting EBERs (EBER-ISH) and the BamHI-W region of the viral genome (BamHI-W-ISH), and compare the results of both targets. Of the 88 cases collected, 9 were EBER-ISH positive (10.2%), while 33 (37.5%) cases were positive for EBV by BamHI-W-ISH, all showing staining in the nuclei of the malignant cells. No statistically significant results were found between the presence of EBV and carcinoma type, differentiation grade or tumor staging. The kappa agreement index between the two targets was 0.092. Only 4 cases were EBER-ISH(+) and BamHI-W-ISH(-). On the other hand, 28 cases were BamHI-W-ISH(+) and EBER-ISH(-). Altogether, 37/88 (42%) cases were EBV-positive by one or both targets. Infected lymphocytes were verified in 9 (10.2%) and 34 (38.6%) cases, by EBER-ISH and BamHI-W-ISH, respectively. The slight agreement demonstrated between the targets may be due to the lack of expression of EBERs, suggesting that EBV may present a distinct latency pattern in the cervical mucosa, or that it has entered the replicative cycle in some of these tumors, in both cases, explaining the low positivity rate verified through EBER-ISH, while calling into question the latter's gold standard status in the detection of EBV in malignancies. Our findings also indicate that the chosen viral genomic target may represent a suitable candidate for EBV detection by ISH.

A fluorometric hybridization assay for detecting and genotyping high-risk human papillomavirus 16 and 18 in archival tissues of cervical specimens

Early diagnosis and genotyping of high-risk human papillomavirus (HR-HPV) in cervical tissue specimens is significant for cervical cancer prevention. A sensitive microplate fluorometric hybridization assay (MFHA) was designed for the detection of HPV DNA 16 and 18 in cervical tissue. Following optimization and validation of the method, 60 formalin-fixed and paraffin-embedded cervical samples representing different cervical intraepithelial neoplasia grades of HPV-associated lesions were tested to determine the sensitivity and specificity of the assay. Using consensus GP5+/6+ biotin-labeled primers to amplify a conserved region within the L1 gene, the amplicons were added to the microplate wells coated with specific probes for the hybridization of HPV 16 and 18 individually. Final detection was performed with streptavidin-AlexaFluor488 conjugated. The results were then compared with type-specific nested polymerase chain reaction (PCR) and colorimetric microplate assay. While the agreement between the results obtained by the type-specific nested PCR and fluorometric assay for the detection of both HR-HPV types was 100%, this agreement for the detection of HPV type 16 and 18 using microplate colorimetric assay was 94.2% and 85% respectively. Overall, the results of the fluorometric and colorimetric assays are promising for detecting both HR-HPV types in a large number of cervical tissue samples with the higher MFHA assay sensitivity.