Stefani Spranger on Checkpoint Blockade Therapies in Melanoma

Stefani Spranger, PhD, postdoctoral fellow, Cancer Research Institute at The University of Chicago Medicine, discusses immune checkpoint blockade therapies that are currently being used to treat patients with melanoma.

Checkpoint blockade therapies target immune inhibitory molecules on CD8-positive T cells, explains Spranger. By blocking those immune inhibitory pathways, the cells are essentially reactivated, and they regain their function to fight the cancer.

Spranger also sheds light on the need to identify predictive and precise biomarkers in melanoma. Currently, most research looks at PD-L1 expression as a biomarker for patients. PD-L1 is upregulated in response to T-cell activation molecules that are secreted by T cells, says Spranger. Thus, PD-L1 expression is an indicative marker of the presence of CD8-positive T cells on the tumor.

However, Spranger delves into some of the imperfections associated with this biomarker, as well. Some tumor cells have intrinsic methods to upregulate PD-L1, which would mean there is no presence of T cells, and this can lead to false positives. In the future, Spranger hopes to see genomic-based approaches to ensure the certainty of the presence of T cells within the tumor microenvironment.