CHRNA7 and neuroblastoma: The incorporation of dupα7 and dupΔα7 (exon six of CHRFAM7A harbors a 2-bp deletion polymorphism) subunits modestly changes the sensitivity of receptors to choline and varenicline in mouse neuroblastoma Neuro2a cells [18], while the stable overexpression of dupα7 inhibits α7nAChR-induced intracellular concentration of Ca2+ signaling and exocytotic responses in human SH-SY5Y cells [31].