Programmed death 1 (PD-1) immunotherapy may have activity against basal cell carciniomas (BCCs), including in those that have been previously treated, a recent study found. This investigation was a cross-sectional study at a single academic tertiary referral center. Immunohistochemical staining on formalin-fixed BCCs were examined in masked fashion by a dermatopathologist and a dermatologist from March 31, 2014, to June 7, 2016. They found:

• Among 138 BCCs from 62 patients (43 males and 19 females; mean [SD] age at biopsy, 61.6 [13.7] years), 89.9% (124 of 138) were positive for programmed death ligand 1 (PD-L1) expression in tumor cells, and 94.9% (131 of 138) were positive for PD-L1 expression in tumor-infiltrating lymphocytes (TILs), defined as greater than 5% positive immunohistochemical staining in the respective cell populations.
• The PD-L1 immunohistochemical staining intensity of 78 treated BCCs compared with 60 treatment-naive BCCs was significantly different in tumor cells (32% vs 7%) and TILs (47% vs 18%) after adjusting for age at diagnosis.