MSCs have no effect on PyMT or Neu oncogene-induced breast cancer.

<p>Female TVA transgenic mice (8–10 weeks old) were infected by intraductal injection of RCAS-PyMT virus-infected DF-1 cells (2×10⁵ cells/gland), 4 glands per mouse. Mice were treated with PBS or MSCs [2×10⁶ cells/mouse) once (<b>A & C</b>) by i.v. injection one week later or treated with MSCs weekly for 4 weeks (<b>B & D</b>)]. Mice were monitored for tumor formation by palpation. Fractions of tumor-free mammary glands infected with RCAS-PyMT DF-1 cells (<b>A & B</b>) or tumor-free mice (<b>C & D</b>) were shown by Kaplan-Meyer plot. Mice were sacrificed two months later. Tumor nodules were harvested. Tumor weight was recorded and statistically analyzed by using Student <i>t</i>-test (<b>E & F</b>). (<b>G & H</b>) TVA transgenic mice infected with RCAS-Neu virus by intraductal injection of RCAS-Neu virus-infected DF-1 cells (2×10⁵ cells/gland), 4 glands per mouse. Mice were treated three weeks later with PBS or MSCs [2×10⁶ cells/mouse) by i.v. injection biweekly for 8 weeks. Mice were monitored for tumor formation by palpation. Fractions of tumor-free mammary glands (<b>G</b>) or tumor-free mice (<b>H</b>) infected with RCAS-Neu virus were shown by Kaplan-Meyer plot.