PAX6 is a member of the paired box family of transcription factors expressed in the developing sensory organs (including eye, nasal and olfactory tissues), central nervous and endocrine system. The expression of PAX6 is sustained in the neuroendocrine system of adults.

PAX6 labels neuroendocrine cells and derived tumor cells. A recent study showed that PAX6 is positive in the majority of neuroendocrine tumors originated from pancreas, duodenum, and colon. PAX6 might be helpful in identification of neuroendocrine tumors.