5071 - Expression of estrogen receptor and programmed cell death-ligand 1 can be complementary prognostic factors in HPV-positive oropharyngeal squamous cell carcinoma

Background

Oropharyngeal squamous cell carcinoma (OPSC) continues to increase in incidence with human papillomavirus (HPV) infection. Despite the good overall prognosis, it needs to assess the risk of not only survival, but also the risk of local, regional, or distant treatment failure to guide de-intensification regimens. This study aimed to investigate the expression of estrogen receptor (ER) and programmed cell death-ligand 1 (PD-L1) proteins according to the status of HPV infection and their prognostic implication in OPSCC patients.

Methods

Consecutive 80 patients diagnosed with OPSCC with surgical treatment from 2004 to 2017 were included. Immunohistochemistry for ER and PD-L1 was performed formalin-fixed, paraffin embedded tissues. HPV status assessed with p16 immunohistochemistry and HPV DNA testing.

Results

ER and PD-L1 expression were observed in 37.5% (30/80) and 60% (48/80), respectively. Both ER and PD-L1 protein expression were higher in HPV-positive OPSCC than in HPV-negative subgroup (47.5% vs. 9.5% for ER, 66.1% vs. 42.9% for PD-L1). There was no significant association between ER and PD-L1 expression (correlation coefficient: 0.105, p > 0.05). Using Kaplan-Meier curves, PD-L1 expression was associated with longer recurrence-free duration (p = 0.013), whereas ER expression was associated with prolonged overall survival (p = 0.043). In subgroup analysis, PD-L1 expression was found to be an independent excellent prognostic factor for recurrence-free duration in HPV-positive OPSCC (p = 0.002, HR = 0.085 [0.018-0.399]). ER expression also tended to be associated with longer overall survival in the HPV-positive OPSCC subgroup, but no statistical significance was observed. In HPV-negative subgroup, both ER and PD-L1 expression were not associated with any clinicopathologic factor nor survival.

Conclusions

ER and PD-L1 expression can be complementary prognostic factors in HPV-positive OPSCC. It may allow us to investigate the independent role of anti-hormone receptors and the tumor microenvironment in the treatment of OPSCC.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.