Expression of programmed death-ligand 1, topoisomerase IIα and p16 proteins in cervical cancer and their significances

Abstract

Objective To analyze the expression of programmed death ligand 1 (PD-L1), p16 proteins and DNA topoisomerase Ⅱα (TOPOⅡα) in cervical cancer and their clinical significances. Methods A total of 181 paraffin-embedded operating specimens and the biopsy including 106 cervical squamous cell carcinoma, 30 high grade cervical intraepithelial neoplasia (CIN), 30 low grade CIN and 33 normal cervical were selected from January 2014 to December 2015. An immunohistochemical EnVision method was used to detect the expression of PD-L1, p16 and TOPOⅡα. Results The positive rate of PD-L1 expression in cervical squamous cell carcinoma was 66.0% (70/106), but it was not expressed in high grade CIN, low grade CIN and normal cervical tissues, the differences were statistically significant (all P= 0.000). Whereas, in squamous cell carcinoma, the positive rate of PD-L1 in poor differentiation group [77.3% (51/66)] was higher than that in middle or high differentiation group [56.5% (21/40)], and the difference was statistically significant (χ2= 7.02,P= 0.01). According to the FIGO stage, the positive rate in stage Ⅰ-Ⅱ group [54.9% (28/51)] was lower than that in stage Ⅲ-Ⅳ group [76.4% (42/55)], and the difference was statistically significant (χ2= 5.47, P= 0.02). But there was no statistical significance in lesion size or lymph node metastasis (both P > 0.05). The positive rate of p16 in cervical squamous cell carcinoma was 99.1% (105/106), in high grade CIN was 86.7% (26/30), in low grade CIN was 26.7% (8/30), and no expression in normal cervical tissues, the differences were statistically significant (all P 0.05). The positive expression rate of TOPOⅡα in cervical squamous cell carcinoma was 97.2% (103/106), compared with that in high grade CIN [73.3% (22/30)], low grade CIN [66.7% (20/30)], and normal cervical tissues (no expression), the differences were statistically significant (all P= 0.000). But there was no significant difference in the positive expression rate of TOPO Ⅱα between high grade and low grade CIN (χ2= 0.32, P= 0.570). The expression of TOPOⅡα had no relationship with histological differentiation, FIGO stage, lesion size and lymph node metastasis (all P > 0.05). Conclusion The expression of PD-L1, p16 and TOPOⅡα is associated with the invasion of cervical cancer.PD-L1 may be an immune checkpoint for the treatment of patients with invasive cervical cancer. Key words: Uterine cervical neoplasms; DNA topoisomerases, type Ⅱ; Programmed death ligand 1; Genes, p16