SignificanceIn this study, we identify nerve-released glial cell line-derived neurotrophic factor (GDNF) family receptor (GFR)α1 as a key factor that enhances perineural invasion (PNI) through GDNF-Ret proto-oncogene (RET) signaling. We demonstrate that GFRα1 is released from nerves in a soluble form and cooperates with secreted GDNF to activate cancer cell surface RET, activating downstream signaling, cancer cell migration, and PNI. These findings advance our understanding of the molecular mechanisms of PNI and define the specific cancer cell requirements necessary for PNI to occur. This work promotes the concept that a ligand and receptor both released by the microenvironment may cooperate together to facilitate cancer invasion. These findings highlight the key participatory role that the nerve microenvironment plays in enabling cancer perineural invasion.