During recent decades of years

animal experiments and preclinical studies have shown that nanosecond pulsed electric fields（nsPEFs） have characteristics with high energy

minimally invasive

approach without combined chemotherapy drugs. Consequently

we applied ns PEFs to MDA–MB–231 breast cancer bearing mice to observe the ablation effect of local primary tumor. The immune stimulation effect of local ablation on the T cell subsets were explored to investigate its immune mechanism as a non-thermal ablation. The mice with normal immune function were subcutaneously inoculated with breast cancer MDA–MB–231 cells for 2 weeks till the tumor diameter was around 10 mm. The ns PEFs treatment parameters were selected to be pulse duration 300 ns

electric field strength 40 k V/cm and pulse number 100 pulse

3 treatments every other day. The tumor formation rate was 100%. The tumor size

morphology and volume were followed up to 1 month. The animals were euthanized when the tumor volume was 20 mm. The ablation rate of the local tumor was 83%

and the volume of the primary tumor in ablation group was significantly lower than that of the control group. The flow cytometry was used to detect the spleen lymphocyte subsets. After ablation

the number and proportion of CD4 + T cells and CD8 + T cells in the spleen of mice were increased

suggesting that the localized nanosecond pulse stimulated the proliferation of spleen T cells. The results reveal that the ns PEF ablation can not only inhibit the primary tumor

but also enhance the immune function of mice

making the tumor growth and metastasis invasiveness decreased

help to inhibit tumor formation and development.