ADGRL4 and neoplasm: Remaining questions that should be further examined include: (1) an investigation of the association between ELTD1 and GPR125 expression from the primary tumor throughout Rb development and progression as tumor metastasizes; (2) identification of ELTD1-associated mechanisms contributing to regulating Rb migration and invasion and, (3) examination of ELTD1’s role in Rb angiogenesis.