Figure 1: N1-S1-Luc HCC tumor sizes 14 days post-nsPEFs treatment. – N1- S1 cells were transfected with the gWiz-Luc plasmid driven by the CMV IE promoter (Aldevron, Madison WI). Clones were isolated as stable transfectant and the clone with the highest expression level was used. A liver lobe from Sprague Dawley rats (Harlan, Frederick MD) was exposed through a small incision in the abdomen and rat N1-S1-Luc HCC cells (1x106) (N1-S1 from ATCC) were injected under the liver capsule. Seven days later, the liver lobe was again exposed though an abdominal incision and tumors (~0.5 cm in diameter) were treated with various pulse numbers with durations of 100 ns, electric fields of 50 kV/cm at 1 Hz (n=8 for all groups). Rats were humanely euthanized 14 days after treatment. Treated lesions were excised to determine volume (A) and weight (B). Tumor volumes were determined using the formula for prolatespheroids (square of the width x length x 0.52): V = 0.52 x (D1 x D2) x2, where D1 and D2 are short and long tumor diameters, respectively. The symbols “*” indicates statistical significance compared with the zero pulse group. P values were calculated using a one-way ANOVA followed by Tukey tests (* p<0.05, ** p<0.01 ***p<0.001).