This nanoelectroablation therapy effectively treats subdermal murine allograft tumors, autochthonous basal cell carcinoma (BCC) tumors in Ptch1+/−K14-Cre-ER p53 fl/fl mice, and UV-induced melanomas in C57/BL6 HGF/SF mice. Here we describe the first human trial of this modality. We treated 10 BCCs on three subjects with 100–1000 electric pulses 100 ns in duration, 30 kV/cm in amplitude, applied at 2 pulses per second. Seven of the 10 treated lesions were completely free of basaloid cells when biopsied and two partially regressed. Two of the 7 exhibited seborrheic keratosis in the absence of basaloid cells. One of the 10 treated lesions recurred by week 10 and histologically had the appearance of a squamous cell carcinoma. No scars were visible at the healed sites of any of the successfully ablated lesions. One hundred pulses were sufficient for complete ablation of BCCs with a single, one minute nanoelectroablation treatment.

Summary Non-thermal nanoelectroablation therapy completely ablates UV-induced murine melanomas. C57/BL6-HGF/SF transgenic mice were exposed to UV radiation as pups and began to develop visible melanomas 5–6 months later. We have treated 27 of these melanomas in 14 mice with nanosecond pulsed electric field (nsPEF) therapy delivering 2000 electric pulses each 100 ns long and 30 kV/cm at a rate of 5–7 pulses per second. All nanoelectroablated melanoma tumors began to shrink within a day after treatment and gradually disappeared over a period of 12–29 days. Pyknosis of nuclei was evident within 1 h of nsPEF treatment, and DNA fragmentation as detected by TUNEL staining was evident by 6 h after nsPEF treatment. In a melanoma allograft system, nsPEF treatment was superior to tumor excision at accelerating secondary tumor rejection in immune-competent mice, suggesting enhanced stimulation of a protective immune response by nsPEF-treated melanomas. This is supported by the presence of CD4+-T cells within treated tumors as well as within untreated tumors located in mice with other melanomas that had been treated with nanoelectroablation at least 19 days earlier.

We have identified an effective nanoelectroablation therapy for treating pancreatic carcinoma in a murine xenograft model. This therapy initiates apoptosis in a nonthermal manner by applying low energy electric pulses 100 ns long and 30 kV/cm in amplitude to the tumor. We first identified the minimum pulse number required for complete ablation by treating 30 tumors. We found that the minimum number of pulses required to ablate the tumor with a single treatment is between 250 and 500 pulses. We settled on a single application of either 500 or 1000 pulses to treat pancreatic carcinomas in 19 NIH-III mice. Seventeen of the 19 treated tumors exhibited complete regression without recurrence. Three mice died of unknown causes within 3 months after treatment but 16 lived for 270–302 days at which time we sacrificed them for histological analysis. In the 17 untreated controls, the tumor grew so large that we had to sacrifice all of them within 4 months.

Background Breast cancers (BC) that arise in individuals heterozygous for a germline pathogenic variant in a susceptibility gene, such as BRCA1/2, PALB2 and RAD51C, have been shown to exhibit bi-allelic loss in the respective genes, and be associated with triple-negative (TN) BC and distinctive somatic mutational signatures. Tumour sequencing thus presents an orthogonal approach to assess the role of candidate genes in BC development. Methods Exome sequencing was performed on paired normal-breast tumour DNA from 124 carriers of germline loss-of-function (LoF) or missense (MS) mutations carriers in 15 known and candidate BC predisposition genes identified in the BEACCON case-control study. Bi-allelic inactivation and association with tumour genome features including mutational signatures and homologous recombination deficiency (HRD) score were investigated. Results BARD1-carrying TN BC (4/5) displayed bi-allelic loss and associated high HRD scores and mutational signature 3, as did a RAD51D-carrying TN BC and ovarian cancer. Bi-allelic loss was less frequent in BRIP1 BCs (4/13) and had low HRD scores. In contrast to other established BC genes, BCs from carriers of CHEK2 LoF (6/17) or MS (2/20) carriers had low rates of bi-allelic loss. Exploratory analysis of BC from carriers of LoF mutations in candidate genes such as BLM, FANCM, PARP2 and RAD50 found little evidence of bi-allelic inactivation. Conclusions BARD1 and RAD51D behave as classic BRCA-like genes with bi-allelic inactivation but this was not observed for any of the candidate genes. However, as demonstrated for CHEK2, the absence of bi-allelic inactivation does not provide definitive evidence against the gene’s involvement in BC predisposition.

We have developed a low energy direct current pulsed electric field therapy for tissue ablation. This therapy applies 100 ns long electric pulses 30 kV/cm in amplitude using a contact electrode and triggers apoptosis in the treated tissue. Here we review the progress that has been made in understanding the mechanisms and targets of nanosecond pulsed electric fields (nsPEF) when applied to cells and tissues. This work began in 2001 in the laboratory of Karl Schoenbach who collaborated with biologists Stephen Beebe and Stephen Buescher to demonstrate the permeabilization of intracellular organelles. Since then over 100 papers have been published studying the cellular responses to nsPEF. We discuss these targets and cellular responses and introduce some new results from our group using nanoelectroablation to treat human pancreatic carcinoma in a murine xenograft model system. We have determined that 500 pulses 100 ns long and 30 kV/cm in amplitude are sufficient to ablate human pancreatic carcinomas growing in immunosuppressed mice and these ablated tumors do not recur for at least 300 days. We have also determined that the reactive oxygen species generation that is triggered within a minute after nsPEF treatment is Ca 2+ -dependent. In order bring this therapy into the clinic for the treatment of human tumors we are developing both a pulse generator as well as delivery electrodes to target the tumors to be treated. We describe the NanoBlate ® Model NB-1 100 ns pulse generator and the first human clinical trial data using nanoelectroablation to ablate basal cell carcinomas without scarring.