Based upon the fact that MSCs could express antibodies in targeting multiple receptors on the surface of tumor cells and tumor-promoting factors in tumor microenvironment (TME) [20, 21], in this study we designed to establish a Tandem diabody and construct UCMSCs-Tandab(IL-6/CD20) and validated its therapeutic effect on DLBCL. The gene discussed is IL6; the disease is diffuse large B-cell lymphoma.