Laminin-5 gamma 2 chain expression in cervical intraepithelial neoplasia and invasive cervical carcinoma

To analyze the expression of laminin-5 gamma 2 chain, a protein which plays a major role in keratinocyte migration, in cervical intraepithelial neoplasia (CIN), and invasive cervical carcinoma associated with high-risk oncogenic human papillomaviruses (HR-HPVs).

The expression of laminin-5 gamma 2 chain protein has been analyzed by immunohistochemistry in 17 cases of low-grade squamous intraepithelial lesions (LSIL-CIN1), 35 high-grade squamous intraepithelial lesions (HSIL-CIN2/3), 18 microinvasive or invasive carcinomas, and three metastatic lymph nodes. All these lesions have been proved to contain HR-HPVs and were also positive for p16 protein which classically is overexpressed at all stages of cervical neoplasia and dysplasia linked with HR-HPVs. 20 cases of normal cervix served as controls.

The expression of laminin-5 gamma 2 chain protein was observed in 100% of invasive or microinvasive carcinoma and in their related lymph node metastasis with an immunoreactivity located preferentially at the invasive front of the lesions. All the HSILs (100%) associated with invasive carcinoma were also positive. In contrast, in HSILs without associated invasive component, the expression of the protein has been found in only 34% of cases. In positive HSILs, laminin-5 gamma 2 protein was expressed in basal layers. In LSILs and normal epithelium, no expression of the protein was noted.

We conclude the following: (i) the expression of laminin-5 gamma 2 is a late event in cervical carcinogenesis increasing with the grade of dysplastic lesions; (ii) laminin-5 gamma 2 expression facilitates the identification of invasive and microinvasive lesions which could be difficult to diagnose on the basis of routine stains; (iii) laminin-5 gamma 2 expression in HSILs could potentially identify those lesions with a more increased risk of tumor progression.