Regulator of G-protein signaling 1 and regulator of G-protein signaling 4 gene expression was up-regulated and down-regulated, respectively, in diffuse-type gastric cancer. A: regulator of G-protein signaling 1 (RGS1) gene expression was up-regulated in diffuse-type gastric cancer (GC) compared with early-stage mesenchymal stem cell (MSC) cultures [n = 5 in early-stage MSC cultures (B#4, C#4, F#5, G#4, and H#4), n = 5 in late-stage MSC cultures (B#28, C#24, E#28, G#28, and H#28), and n = 5 in diffuse-type GC (GC16, GC40, GC54b, GC60, and GC23s)]. Results represent the mean ± SE. bP < 0.01 using a one-way analysis of variance with Bonferroni’s multiple comparisons test; B: RGS4 gene expression was down-regulated in diffuse-type GC compared with MSCs. Results represent the mean ± SE (n = 12 in MSC cultures and n = 5 in diffuse-type GC). bP < 0.01 and dP < 0.001 using Student’s t test with the non-equal variance hypothesis.