While other NAP1 family members, e.g., NAP1L2, NAP1L3, and NAP1L5 [11-14] are well known to be neuron-specific and play a role in proliferation [15] and the NAP1 family is associated with transcriptional regulation [8], our current results define a role for NAP1L1 in the transcriptional regulation of pancreatic neuroendocrine neoplasm cell cycle progression. This evidence concerns the gene NAP1L1 and pancreatic neuroendocrine neoplasm.