Alexander I. Sankin, MD, an assistant professor of Urology at Montefiore Medical Center at the Albert Einstein College of Medicine, discusses a preclinical study which investigated HHLA2— a recently defined new checkpoint “family member”— in urothelial carcinoma.
The goal of the study was to look for ligands beyond PD-L1 that may be targetable in bladder cancer, said Sankin. HHLA2 receptors are in the same family and seem to have similar biologic activity to PD-L1, but have not yet been studied in most cancer types.
By using human bladder cancer specimens, Sankin and his team stained for HHLA2, also known as B7H7.
They found that HHLA2 is expressed in about 66% of the tumors they looked at. This is an important take-home message, because PD-L1 is only expressed in about 20% to 25% of tumors, so this seems to be even more highly expressed and it might be even more biologically relevant, said Sankin.