When increasing number of the three stem cell lines (8.0×103, 1.6×104 and 2.4×104 cells/well) were cultured with AGS and equally treated with 5-FC at 500 μg/ml, HB1.F3.CD cells expressing the CD gene and HB1.F3.CD.IFN-β cells expressing both the CD and IFN-β fusion genes appeared to show maximum cancer cell growth inhibition starting at a 1:2 ratio of stem cells:AGS, results with higher stem cells number showed similar inhibition effects. The gene discussed is IFNB1; the disease is cancer.