BDNF and pachyonychia congenita: These survey responses support local pancreatic tumor invasion of the local or communicating neural sheaths and ensuing disruption or ongoing release of neurotransmitters (eg, 5-HT, BDNF, CGRP, and NE) to produce or enhance GI tract pathology.28-31 Systemically, significantly increased associations of pre-diagnosis PC pain and impairment of functioning and mood were reported, consistent with previous reports.7,9,32