H pylori enhances the proliferation and migration of BM‐MSCs in vitro and promotes tumour growth in nude mice. A, Representative CFSE‐labelled BM‐MSCs after coculture with the supernatant of H pylori (MOI: 0, 10, 50, 100, 12 h). B, Percentage of cells in M1 in in vitro coculture with the supernatant of H pylori (MOI: 0, 10, 50, 100, 12 h). C, Transwell migration assay of BM‐MSCs cocultured in vitro with H pylori lysed by ultrasonication (MOI: 50, 18 h). D, Representative images of tumours in nude mice 1 or 2 weeks after injection of MFCs alone or co‐injection of MFCs and BM‐MSCs. E, Tumour size in the control, BM‐MSCs, MFC and MFC +BM‐MSCs groups (n = 6; *** P <.001). F, Representative Ki‐67 IHC images and quantitative analysis of the Ki‐67 index of tumour sections from the MFC and MFC +BM‐MSCs groups are shown. *** P <.001. G, Dual immunofluorescence analysis of GFP (green) and α‐SMA (red) in the MFC +BM‐MSCs group. Nuclei were labelled with DAPI (blue). H, BM‐MSCs promote the metastasis of gastric cancer xenograft tumours in nude mice. Representative PET‐CT images of nude mice 3 weeks after injection of MFCs alone or co‐injection of MFCs with BM‐MSCs in the right armpit are shown. The white circles indicate suspected abdominal metastasis of subcutaneous xenograft tumours in the MFC +BM‐MSCs group at 3 weeks post‐transplantation. Mip, Maximal Intensity Projection. Results are expressed as means ±SD. **P <.01, ***P <.001