In small 30-50mm3 4T1 mouse tumors, 1x106 XMCs isolated from porcine mammary glands were delivered i.t. once, along with three doses of gemcitabine delivered weekly i.p. The XMC treatment led to tumor growth delay, with higher percentages of necrotic areas and apoptotic cells and fewer Ki67+ proliferating cells. This evidence concerns the gene MKI67 and neoplasm.