Based on limited published evidence, SYT15B is a synaptotagmin family protein with canonical functions in calcium-dependent phospholipid binding and calcium ion sensor activity, localized to exocytic vesicles and the plasma membrane. It regulates calcium ion-dependent exocytosis through SNARE binding and vesicle-mediated transport. Recently, SYT15B was identified as an oncogenic driver in lung adenocarcinoma, where elevated expression promotes tumor progression through calcium-dependent interaction with IQGAP1, leading to MAPK pathway activation and aggressive phenotypes 1. These findings suggest SYT15B functions beyond canonical exocytosis in cellular signaling and cancer biology.