Based on limited published evidence, PCDHGB5 is a calcium-dependent cell-adhesion protein predicted to function in establishing and maintaining neuronal connections through cell-cell adhesion mechanisms. The protein localizes to the plasma membrane and extracellular exosomes, with binding capacity for other cell adhesion molecules. Recent genomic analysis identified PCDHGB5 among genes associated with cyclophosphamide response and prognostic significance in breast cancer 1, though the mechanistic basis for this association remains unexplored.