CD38 and neoplasm: This investigation highlighted three fundamental steps of this synergistic pathway: (1) activation of intracellular CD38 by protein kinase A following NK cell recognition of a tumour cell results in ADPR production; (2) ADPR targets TRPM2 channels on cytolytic granules, and (3) TRPM2-mediated Ca2+ signalling causes cytolytic granule polarisation and degranulation, resulting in anti-tumour activity [28].