NCAM1 and atrial fibrillation: Differential expression of five of these genes was then confirmed using quantitative real-time PCR (qRT-PCR) on NP, AF and AC cells, which demonstrated that α-2-macroglobulin (A2M), cytokeratin-18 (KRT18) and neural cell adhesion molecule (NCAM1) were enhanced in NP compared with AC cells.