Dr. Succaria on Targetable Immune Checkpoints in Head and Neck Cancer

Farah Succaria, MD, postdoctoral fellow, Johns Hopkins Medicine, discusses targetable immune checkpoints in head and neck squamous cell carcinoma (SCCHN).

Investigators are currently trying to identify potential targetable immune checkpoints in the tumor microenvironment of SCCHN. This is in an effort to inform rational combination therapy development, according to Succaria. While PD-1 is the only established immune checkpoint in SCCHN, targets under investigation include TIM-3, LAG-3, FoxP3, GITR, IDO, and PD-L2. Immunohistochemistry for these markers, as well as CD3, CD4, CD8, CD20, and CD68, was quantified using HALO image analysis for density of positive cells.

In 27 specimens, 14 were found to be HPV-negative and 13 were HPV-positive. After the density of each of the markers was assessed and exported into the HALO server, Succaria could then tell which cells were tumor cells, and which were immune cells. Succaria says that she was then able to determine the density of a given marker in the tumor. This allowed investigators to test for multiple markers, not just PD-L1. Findings showed that tumors that were HPV-positive had more T cells, CD3, CD4, CD8, CD20, and PD-1, which was statistically significant. Additionally, there was a trend toward increased density of FoxP3-positive cells in these patients.