ObjectiveTo evaluate the effect of L1 cell adhesion molecule (L1CAM) gene expression silencing by short hairpin RNA (shRNA) on perineural invasion of pancreatic cancer Capan-2 cells in vitro. MethodsWe transfected Capan-2 cells with lentivirus-mediated shRNA targeting L1CAM (L1CAM-shRNA) and negative control shRNA (L1CAM-NC), and then the transfected Capan-2 cells were co-cultured with mouse dorsal root ganglia (DRG) in matrigel matrix. The procession of neurite outgrowth and cell colony growth were observed by inverted microscope. Areas of cell colonies and neurites were quantitated using Image pro plus software. ResultsThe cancer cells migrated to DRG and grew around the neurites in the L1CAM-NC/DRG group, which was not observed in the L1CAM-shRNA/DRG group. On day 3 and 5 of co-culture, the area of cell colonies in the L1CAM-shRNA/DRG group was significantly less than that in L1CAM-NC/DRG group (P<0.01); however, there was no difference in neurite outgrowth between the two groups. ConclusionIt is demonstrated that down-regulation of L1CAM can suppress the perineural invasion of Capan-2 cells in vitro by inhibiting cell proliferation and migration.