Programmed cell death ligand 2 (PD-L2) expression is inversely correlated with human papillomavirus status in oropharyngeal squamous cell carcinoma (OPSCC) tumors.

The incidence of oropharyngeal squamous cell carcinoma (OPSCC) associated with infection by the human papillomavirus (HPV) continues to increase and 71% of OPSCC cases in the United States are HPV+. We have previously performed microRNA profiling of HPV+ vs HPV- OPSCC and identified miR-106b as significantly elevated in HPV + cases (Miller et al., 2015; Am J Path 185:679-92 [1]). MicroRNA target prediction identified the gene PDCD1LG2 as a highly ranked target of miR-106b. This gene corresponds to the protein programmed cell death ligand 2 (PD-L2), a high affinity ligand for the programmed cell death protein 1 (PD-1) receptor on T-cells. The objective of this study was to evaluate PD-L2 expression in a panel of HPV+ and HPV- OPSCC tumors. Using tissues from two distinct patient cohorts, results show significantly lower PD-L2 protein expression levels in HPV+ tumors. These data suggest that future research on regulation of PD-L2 expression in HPV+ OPSCC is warranted.