Increased expressions of claudin-1 and claudin-7 during the progression of cervical neoplasia

Objectives. Claudin proteins represent a large family of integral membrane proteins crucial for tight junction formation and function and they have been shown to be expressed differently in various cancers. We investigated whether the expressions of claudin-1 and claudin-7 are associated with the progression of uterine cervical neoplasia. Methods. We analyzed 89 formalin-fixed paraffin embedded cervical tissues that included 10 normal cervical epithelium, 19 low-grade squamous intraepithelial lesion (LSIL), 20 high-grade squamous intraepithelial lesion (HSIL), 20 invasive squamous cell carcinoma (ISCC) without lymph node (LN) metastasis, and 20 ISCC with LN metastasis. Results. The expressions of claudin-1 and claudin-7 were determined by immunohistochemistry. The expressions of claudin-1 and claudin-7 were undetectable in normal cervical squamous epithelium, but had variable staining in the basal layer of normal endocervical glands. The expressions of both proteins, mainly as membranous staining, gradually increased in accordance with the progression from LSIL to HSIL and ISCC (both P values are <0.001) and were detected in all cases of ISCC. Conclusions. These results suggest that claudin-1 and claudin-7 may play a significant role in tumor progression of cervical neoplasia and may represent useful markers for malignant transformation of cervical squamous cells. Further studies would likely result in the development of novel approaches for early detection and therapy for this disease.