Figure 4

Increase of sphere formation by the remnant living cells isolated from the late-stage primary tumors. (a) Comparison of sphere formation in parental 4T1 cells, original transduced 4T1-PB-2R/PBase cells, and two ex vivo isolated remnant living cells from the late-stage tumors. (b) Quantification of spheres. The sphere numbers were obtained from four random fields examined under the microscope. *P<0.05