RESUMEN
OBJECTIVE: HPV in situ hybridization (ISH) is able to detect HPV DNA and identify integrated HPV DNA by punctuate staining and episomal HPV by diffuse staining in the nuclei. Because the expression of L1 capsid protein disappears after integration of HPV DNA, immunohistochemistry (IHC) of L1 capsid protein can be used as a indirect evidence of integration. Therefore, we tried to evaluate the usefulness of HPV ISH and IHC of L1 capsid protein in Cervical intraepithelial neoplasia (CIN). METHODS: Twenty six cervical lesions from patients with CIN and 19 normal cervical epithelium from patients with leiomyoma were evaluated with HPV ISH and IHC of L1 capsid protein. RESULTS: HPV ISH was positive in 80.8% (21/26) in CIN. Among 21 positive cases, diffuse staining was observed in 42.9% and punctuated and diffuse staining in 57.1%. L1 capsid protein was positive in 65.4% (17/26) of cervical tissue sections and 15.4% (4/26) of cervical smears. The punctuated staining of HPV ISH was correlated with high grade CIN (P=0.007) but expression of L1 capsid protein was not associated with grade of CIN (P>0.05). CONCLUSION: HPV ISH is a useful tool to identify integrated HPV DNA in paraffin-embedded, formalin-fixed cervical tissue. HPV integration confirmed by HPV ISH was associated with high-grade CIN. IHC of L1 capsid protein showed better result using cytology smears than tissue sections.