Programmed Death-1 Pathway in Orbital Invasion of Cutaneous Carcinomas.

PURPOSE: The programmed death-1 pathway negatively regulates the immune system. Previous reports have indicated worse tumor-related outcomes with increased expression of the ligand for this pathway. This study was undertaken to assess the role of the PD pathway in cutaneous malignancies that invade the orbit.

METHODS: Immunohistochemical staining for the programmed death-1 receptor and ligand was performed on exenteration specimens of invasive cutaneous orbital malignancies (n = 12) and nodular basal cell carcinoma (n = 10). The numbers of positively-staining cells/40× field were counted across 5 consecutive fields, and statistical analyses were performed to compare the differences between the 2 groups.

RESULTS: Programmed death-1 receptor positivity was seen in means of 30.9 cells/40× field and 62.4 cells/40× field for nodular basal cell carcinomas and invasive malignancies, respectively (p = 0.0046). A mean of 4.54 cells/40× field stained positively for the programmed death-1 ligand in nodular basal cell carcinoma, whereas a mean of 46.4 cells/40× field stained positively for programmed cell death ligand-1 in orbital invasive cutaneous carcinomas (p = 0.0015). Both of these differences were statistically significant.

CONCLUSIONS: Both the programmed death-1 receptor and its ligand are enriched in invasive cutaneous malignancies. This finding indicates that negative regulation of the immune system likely prohibits tumor surveillance, and facilitates increasing aggressiveness and invasion of cutaneous malignancies.