In vivo tumor treatment experiments. (A) Outline of the treatment regimen with either pcDNA3-ST DNA vaccine or empty vector control pcDNA3. C57BL/6 mice (5 per group) were subcutaneously inoculated with B16/ST tumor (1×105 cells/mouse) in the right flank on D0. Mice were monitored for evidence of tumor growth by visual inspection and palpation. Tumor growth was measured twice a week starting from day 8 after tumor challenge. B16/ST-tumor bearing mice were treated with pcDNA3-MCC/ST or pcDNA3 intradermally with DNA-coated particles using a helium-driven gene gun 3 times at 4-day intervals beginning three days after tumor inoculation. (B) Survival plot depicting the percentage of vaccinated mice surviving following vaccination with either pcDNA3-MCC/ST DNA vaccine or control pcDNA3. (C) Plot depicting tumor volume over time. Tumors were measured with digital calipers and tumor volumes calculated.