Immunochemical assessment of p16 and HPV L1 capsid protein in cervical squamous intraepithelial lesions.

The behavior of the cervical squamous intraepithelial lesions cannot be predicted, many of them, particularly of the low grade type, may disappear without treatment. Invasive cervical carcinoma occurs in approximately 10% of the intraepithelial precursor lesions, being strongly associated with HPV infection. The aim of this study was to make a comparative assessment between immunohistochemical and immunocytochemical expression of p16 and L1 HPV capsid protein respectively, in low grade and high grade cervical squamous intraepithelial lesions.

Methods: The study involved 20 patients with cytological diagnosis of LSIL/CIN1 (low grade squamous intraepithelial lesion/cervical intraepithelial neoplasia) and HSIL (CIN2 and CIN3) (high grade squamous intraepithelial lesion), which underwent a subsequent cervical biopsy. The conventional smears were evaluated for the immunoexpression of L1HPV protein and the corresponding biopsies for the immunoexpression of p16.

Results: The HPV L1 capsid protein was expressed in 46% of LSIL and 24% of HSIL. P16 was positive in 68% of LSIL, 84% of CIN2 and 100% of CIN3. The correlative analysis of p16 status and protein L1HPV expression can be very useful in the assessment of progression risk of cervical squamous intraepithelial lesions.