In contrast to the current study, in previous studies using RANTES-NIS-MSCs [13], MSC recruitment and NIS-mediated tumoral radioiodide uptake were sufficient in subcutaneous HCC xenografts to induce a higher tumor-absorbed dose of 44.3 mGy/MBq followed by a significant therapeutic effect of 131I. This is due to a stronger activation of the native RANTES promoter in the tumor microenvironment. The gene discussed is CCL5; the disease is hepatocellular carcinoma.