TLR4 Downregulation Identifies High-Risk HPV Infection and Integration in H-SIL and Squamous Cell Carcinomas of the Uterine Cervix

Growing scientific evidence suggests a link between the expression of toll-like receptor 4 (TLR4) and cervical cancer carcinogenesis. Specifically, a close relation between TLR4 expression and FIGO stage, lymph node metastases, and tumor size has been reported in cervical cancer. In the present study, we aimed to evaluate the relationship between TLR4 expression levels and human papillomavirus (HPV) infection and/or high-risk (hr) HPV integration status in patients with a histological diagnosis of high-grade squamous intraepithelial lesion (H-SIL), and squamous cell carcinoma (SCC) of the uterine cervix. Sixty biopsies of cervical neoplasia, comprising H-SIL (n = 20) and SCC (n = 40), were evaluated for TLR4 expression by immunohistochemistry. All samples were positive for high-risk HPV as confirmed by in situ hybridization (ISH) and broad-spectrum PCR followed by Sanger sequencing analysis. The intensity of TLR4 staining was higher in tissues negative for intraepithelial lesion or malignancy (NILM) than in H-SIL, and further reduced in SCC. Moreover, statistically significant differences have been observed in the percentage of TLR4 expression between NILM and H-SIL and between H-SIL and SCC, with higher percentages of expression in H-SIL than in SCC. Our results showed a significant downregulation of TLR4 in HPV-related H-SIL and SCC, compared to NILM. These data support the hypothesis that TLR4 expression is suppressed in HPV-driven oncogenesis.