We co-cultured three B-lymphoma cell lines (MA-1, OCI-Ly3, and OCI-Ly7) with HP strains (derived from HPE-responsive gastric MALT lymphoma) and evaluated the expression patterns of CagA, phosphorylated (p)-CagA (CagAP−Tyr), and CagA-signaling molecules, cell-cycle inhibitors, p-NFATc1 (Ser172), and NFATc1 using western blotting. The gene discussed is NFATC1; the disease is gastric mucosa-associated lymphoid tissue lymphoma.