PLXNA2 and familial pancreatic carcinoma: Furthermore, Biankin, AV et al. [20] performed copy number variation (CNV) analysis using exome sequences and arrays of 142 cases of early pancreatic cancer and reported gene mutations in the molecules of the Axon Guidance signal during the embryonic period in addition to the abovementioned 12 cellular signals (slit guidance ligand 2 (SLIT2), roundabout homolog 2 (ROBO2) gene mutation, ROBO1 and SLIT2 copy number decrease, semaphorin 3A (SEMA3A), and plexin-A2 (PLXNA2) copy number increase).