Figure 2: IL-4 expression from cancer cells suppressed tumor grow and metastasis in a nude mouse orthotopic engraftment mode. A: EV-AC2M2 or IL4-AC2M2 cells were engrafted into the fourth mammary glands of nude mice and tumor volume was measured with calipers on day 16 post-engraftment. Tumors were significantly smaller in mice engrafted with IL-4 expressing AC2M2 tumor cells (IL4-AC2M2) compared to those with control tumor cells (EV-AC2M2) (P=0.0239; n=8 for both groups). B: Tumors were resected by recovery surgery on day 16 post-engraftment. On day 28 post-engraftment, mice were sacrificed and lungs were removed for biophotonic imaging of metastatic lesions. 38% (3 of 8) of the lungs harvested from control tumor-bearing mice (EVAC2M2) harbored detectable metastasis while none (0 of 8) of the lungs from IL-4 expressing tumor-bearing mice (IL4-AC2M2) displayed lung metastasis (P=0.0238; n=8 for each group; ND, not detectable). Data shown are representative of two independent experiments.