MLPH (melanophilin) is a Rab effector protein that serves as an adapter linking melanosome-bound RAB27A to the motor protein MYO5A, facilitating melanosome transport and localization to the cell periphery 1. In melanocytes, MLPH regulates melanosome transfer to keratinocytes, controlling epidermal melanin deposition and skin color 2. Beyond its canonical melanosome transport function, MLPH exhibits context-dependent roles in disease. In triple-negative breast cancer, MLPH functions as a tumor suppressor, inhibiting growth and lymph node metastasis through the NONO-SPHK1-S1P axis 3. Conversely, in pancreatic cancer, MLPH promotes metastasis via two distinct mechanisms: (1) inducing primary cilia regrowth under glutamine-deficient conditions through a PLCG1-dependent feedforward loop 4, and (2) enhancing epithelial-mesenchymal transition via PI3K-AKT signaling 5. In glioblastoma, O-GlcNAcylation of MLPH increases radiation resistance by protecting the protein from TRIM21-mediated ubiquitination and activating NF-κB signaling 6. MLPH fusion with ALK has been identified in melanoma 7. Additionally, MLPH hypermethylation correlates with coronary heart disease and myocardial infarction risk, particularly in younger males 8. These findings suggest MLPH has pleiotropic functions extending beyond melanosome transport into cancer progression and cardiovascular disease.