Programmed Death Ligand-1 Expression Is Associated With Poorer Survival in Anal Squamous Cell Carcinoma

* Context.--Upregulation of programmed death ligand-1 (PD-L1), an immunoregulatory protein, is associated with an adverse outcome in several malignancies. Very few studies have evaluated PD-L1 expression in invasive anal squamous cell carcinoma (ASCC). Objective.--To assess PD-L1 expression in patients with ASCC and correlate it with clinicopathologic factors and clinical outcomes. Design.--Fifty-one cases of ASCC were immunostained for PD-L1. PD-L1 expression by combined positive score and tumor proportion score was correlated with age, sex, HIV status, HIV viral load, CD4 count, stage, and outcomes. Kaplan-Meier curves for overall survival were plotted and compared using the log-rank test. Cox regression analysis was performed to identify significant prognostic factors (2-tailed P < .05 was considered statistically significant). Results.--PD-L1 was positive in 24 of 51 cases (47%) by combined positive score and in 18 of 51 (35%) by tumor proportion score. The median cancer-specific survival and 5-year overall survival were significantly lower in [PD-L1.sup.+] patients. Age, sex, HIV status, HIV viral load, stage, and cancer progression were not significantly different between the 2 groups. CD4 count of more than 200/[micro]L was significantly higher in [PD-L1.sup.+] patients. [PD-L1.sup.+] status remained statistically significant for worse overall survival on multivariate analysis. Conclusions.--[PD-L1.sup.+] status is an independent adverse prognostic factor for overall survival in ASCC. This study highlights the potential of PD-L1 targeted therapy in better management of ASCC. (Arch Pathol Lab Med. 2022;146:1094-1101; doi: 10.5858/arpa.2021-0169-OA)
Although anal squamous cell carcinoma (ASCC) is a rare malignancy, making up only 0.5% of all cancer cases in the United States, alarmingly, the annual incidence continues to rise both [...]